fix(e2e): track the test fixtures the suite reads

`.gitignore` carried an unanchored `media/`, commented "Media uploads (mounted volume in
production)". Production media lives in the `media_data` Docker volume and never
appears in the working tree, so that rule guarded nothing real — but unanchored it
matches a directory of that name at ANY depth, and the only one in the repo is
`e2e/fixtures/media/`.

Its entire practical effect was to keep every E2E fixture untracked. A fresh clone got
the specs and none of the images or videos they read, and
`.github/workflows/e2e.yml` does a plain `actions/checkout` and generates nothing — so
the committed CI job could not have run the upload, video, EXIF, quota, oversized-image
or export suites at all. It only ever looked green locally, where the fixtures survive
as untracked leftovers from whoever first created them.

The `origin` remote is git.mc02.dev rather than GitHub, so those workflows have most
likely never executed against this repo, which is consistent with nobody noticing. That
also makes this a live blocker for the standing "rotate the token and push" item: the
first time CI runs, it fails on ENOENT in a way that looks like a broken suite rather
than a missing file.

Anchors the pattern to `/media/` and commits the six fixtures (672 KB total). Verified
`e2e/fixtures/media` is the ONLY directory the old pattern matched, so nothing else
changes visibility.

Found while adding `sample-5s.mp4` for the video-poster work: the new fixture would
have been invisible to every other machine, which is how the existing ones got here.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.env.example

@@ -12,6 +12,14 @@ APP_ENV=production
 # ── Database ──────────────────────────────────────────────────────────────────
 # Set a strong password and keep it in sync between DATABASE_URL and
 # POSTGRES_PASSWORD. Generate one with: openssl rand -hex 24
+#
+# SET THIS BEFORE THE FIRST `docker compose up -d`. Postgres reads POSTGRES_PASSWORD
+# only when it initialises its data directory, on that very first boot. Change it
+# afterwards and the app authenticates with the new password against a volume still
+# holding the old one — a permanent restart loop ("password authentication failed").
+# The only ways out are restoring the old password or `docker compose down -v`, which
+# deletes the database, the media and the exports. In production the app refuses to
+# boot while this is still the placeholder below, so it cannot be missed by accident.
 DATABASE_URL=postgres://eventsnap:CHANGE_ME_use_a_strong_password@db:5432/eventsnap
 POSTGRES_USER=eventsnap
 POSTGRES_PASSWORD=CHANGE_ME_use_a_strong_password
@@ -30,7 +38,9 @@ JWT_SECRET=change_me_to_a_random_64_byte_hex_string
 SESSION_EXPIRY_DAYS=30
 
 # Admin dashboard password (bcrypt hash).
-# Generate with: htpasswd -bnBC 12 "" yourpassword | tr -d ':\n'
+# Generate with an image the stack already pulls (htpasswd needs apache2-utils, which
+# a stock VPS does not have):
+#   docker run --rm caddy:2-alpine caddy hash-password --plaintext 'yourpassword'
 # IMPORTANT: keep the SINGLE QUOTES. A bcrypt hash is full of `$` (e.g. $2b$12$…$…),
 # and both Docker Compose's env_file interpolation and dotenvy's variable substitution
 # would otherwise eat the `$…` segments (reading them as unset vars) and corrupt the

.gitignore

@@ -13,8 +13,16 @@ frontend/build/
 frontend/export-viewer/node_modules/
 frontend/export-viewer/.svelte-kit/
 
-# Media uploads (mounted volume in production)
-media/
+# Media uploads. In production these live in the `media_data` DOCKER VOLUME, never in the
+# working tree — so this pattern is anchored to the repo root and exists only for a local
+# bind-mount experiment.
+#
+# It used to read `media/`, unanchored, which matches a directory of that name at ANY depth.
+# The only one in the repo is `e2e/fixtures/media/`, so the rule's entire practical effect was
+# to keep every E2E fixture untracked: a fresh clone got the specs and none of the images or
+# videos they read. `.github/workflows/e2e.yml` does a plain checkout and generates nothing, so
+# the committed CI job could not have run the upload, video or export suites at all.
+/media/
 
 # Playwright E2E suite — runtime artifacts (the suite itself is committed)
 e2e/node_modules/

README.md

@@ -97,17 +97,51 @@ eventsnap/
 git clone https://git.mc02.dev/fabi/EventSnap.git eventsnap
 cd eventsnap
 
-# 2. Configure environment
+# 2. Configure environment — set EVERY secret NOW, before step 3.
 cp .env.example .env
-nano .env   # set DOMAIN, JWT_SECRET, ADMIN_PASSWORD_HASH, EVENT_NAME, etc.
+nano .env   # DOMAIN, EVENT_NAME, EVENT_SLUG,
+            # JWT_SECRET, ADMIN_PASSWORD_HASH,
+            # POSTGRES_PASSWORD *and* the same password inside DATABASE_URL
+            # (see "Generate required secrets" below)
 
 # 3. Start the stack
 docker compose up -d
 ```
 
+> **Set every secret before step 3 — `POSTGRES_PASSWORD` especially.** Postgres reads it **only
+> when it initialises its data directory**, which happens on the very first `docker compose up -d`.
+> Changing it in `.env` afterwards does not change the stored password: the app then authenticates
+> with the new one against a volume holding the old one, and you get a permanent restart loop with
+> `password authentication failed for user "eventsnap"`. The only fixes are restoring the old
+> password or `docker compose down -v`, which **deletes the database, the media and the exports**.
+> Getting it right once, up front, costs nothing; getting it wrong costs the volume.
+
 Caddy automatically obtains a Let's Encrypt certificate on first start. The app is live at `https://DOMAIN` within ~30 seconds.
 
-> **If the site never comes up:** with `APP_ENV=production` the backend **refuses to boot** while `JWT_SECRET`/`ADMIN_PASSWORD_HASH` still hold the `.env.example` placeholders (this is deliberate — a publicly-known signing key is worse than downtime). Caddy then waits on the unhealthy `app` container and never serves. Check `docker compose logs app` — a "Refusing to start … placeholder …" line means you skipped step 2. Rotate the secrets (see below) and restart.
+> **If the site never comes up:** with `APP_ENV=production` the backend **refuses to boot** while
+> `JWT_SECRET`, `ADMIN_PASSWORD_HASH` or the password inside `DATABASE_URL` still hold the
+> `.env.example` placeholders (this is deliberate — a publicly-known signing key or database
+> password is worse than downtime). Caddy then waits on the unhealthy `app` container and never
+> serves. Check `docker compose logs app` — a "Refusing to start … placeholder …" line lists
+> **every** unset secret at once, so one edit fixes them all.
+>
+> **If it comes up but keeps restarting with `password authentication failed for user
+> "eventsnap"`:** `POSTGRES_PASSWORD` was changed after the database volume was created. Postgres
+> applies that variable only at initialisation, so `.env` and the stored password have drifted
+> apart permanently. `docker compose logs app` spells this out. Before the event, with nothing
+> worth keeping:
+>
+> ```bash
+> docker compose down -v && docker compose up -d   # -v DELETES db + media + exports. No undo.
+> ```
+>
+> **Once the event has real data, never do that.** Put the original password back into
+> `DATABASE_URL`, or change the stored one instead:
+>
+> ```bash
+> docker compose exec db psql -U "$POSTGRES_USER" -c \
+>   "ALTER ROLE eventsnap WITH PASSWORD 'the-password-now-in-your-.env';"
+> ```
 
 > **Production note:** `docker compose up -d` does **not** expose the database — Postgres is reachable only on the internal Docker network. For local development where you need host access to Postgres, opt into the dev overlay explicitly:
 > ```bash
@@ -179,10 +213,19 @@ TLS certificate and all data volumes survive.
 # JWT secret (64 random bytes)
 openssl rand -hex 64
 
-# Admin password hash (bcrypt, cost 12)
-htpasswd -bnBC 12 "" yourpassword | tr -d ':\n'
+# Database password (goes in BOTH DATABASE_URL and POSTGRES_PASSWORD)
+openssl rand -hex 24
+
+# Admin password hash (bcrypt). Uses an image the stack already pulls, so it needs
+# nothing installed on the host — `htpasswd` lives in apache2-utils, which a stock
+# VPS does not have. Emits cost 14 rather than 12; that is fine (admin login is
+# rate-limited and hashed off the async runtime), and any $2a/$2b/$2y hash verifies.
+docker run --rm caddy:2-alpine caddy hash-password --plaintext 'yourpassword'
 ```
 
+Wrap the resulting hash in **single quotes** in `.env` — see the note there; a bcrypt
+hash is full of `$`, and both Compose and dotenvy would otherwise eat those segments.
+
 ### Environment Variables
 
 See [.env.example](.env.example) for the full list with descriptions and defaults. Key variables:

backend/src/config.rs

@@ -20,21 +20,53 @@ fn looks_placeholder(s: &str) -> bool {
 /// Enforce secret hygiene. In production every guard is hard-fail: a booting app
 /// with a publicly-known signing key is worse than one that refuses to start.
 /// Outside production the dev sentinel is tolerated (warned) so local dev is frictionless.
-fn validate_secrets(is_prod: bool, jwt_secret: &str, admin_password_hash: &str) -> Result<()> {
+///
+/// EVERY failure is collected and reported together. Returning on the first one made fixing two
+/// secrets cost two boot cycles — the operator rotates JWT_SECRET, restarts, and only then learns
+/// about ADMIN_PASSWORD_HASH. Restarting this stack is not free (Caddy waits on the unhealthy app),
+/// and each avoidable cycle is another chance to reach for `down -v`.
+fn validate_secrets(
+    is_prod: bool,
+    jwt_secret: &str,
+    admin_password_hash: &str,
+    database_url: &str,
+) -> Result<()> {
     if is_prod {
+        let mut problems: Vec<&str> = Vec::new();
         if looks_placeholder(jwt_secret) {
-            return Err(anyhow!(
-                "Refusing to start in production with a placeholder JWT_SECRET — \
-                 rotate it (openssl rand -hex 64)."
-            ));
-        }
-        if jwt_secret.len() < 32 {
-            return Err(anyhow!("JWT_SECRET must be at least 32 characters."));
+            problems.push(
+                "JWT_SECRET is still the .env.example placeholder — rotate it \
+                 (openssl rand -hex 64).",
+            );
+        } else if jwt_secret.len() < 32 {
+            problems.push("JWT_SECRET must be at least 32 characters.");
         }
         if admin_password_hash.is_empty() || looks_placeholder(admin_password_hash) {
+            problems.push(
+                "ADMIN_PASSWORD_HASH is unset or still the .env.example placeholder — generate one \
+                 (docker run --rm caddy:2-alpine caddy hash-password --plaintext '<password>').",
+            );
+        }
+        // The DATABASE_URL carries the Postgres password, so a placeholder here means the stack is
+        // running on `CHANGE_ME_use_a_strong_password` — a credential published in the repo. The
+        // app used to boot green on it, because this guard only ever covered the two secrets it
+        // was written for and nothing else looked at POSTGRES_PASSWORD at all.
+        //
+        // Read POSTGRES_PASSWORD's docs before changing this: it is applied ONLY at initdb, so the
+        // remedy is not "edit .env and restart" — see the 28P01 diagnostic in db.rs.
+        if looks_placeholder(database_url) {
+            problems.push(
+                "DATABASE_URL still carries the .env.example placeholder password — set a strong \
+                 one (openssl rand -hex 24) in BOTH DATABASE_URL and POSTGRES_PASSWORD.",
+            );
+        }
+        if !problems.is_empty() {
             return Err(anyhow!(
-                "Refusing to start in production without a real ADMIN_PASSWORD_HASH — \
-                 generate one (htpasswd -bnBC 12 '' <password> | tr -d ':\\n')."
+                "Refusing to start in production — {} secret(s) still unset or placeholder:\n  - {}\n\
+                 ALL secrets must be set BEFORE the first `docker compose up -d`: Postgres bakes \
+                 POSTGRES_PASSWORD into its data directory on first boot and ignores later changes.",
+                problems.len(),
+                problems.join("\n  - ")
             ));
         }
     } else if jwt_secret == DEV_JWT_SECRET_SENTINEL {
@@ -89,11 +121,12 @@ impl AppConfig {
 
         let jwt_secret = std::env::var("JWT_SECRET").context("JWT_SECRET must be set")?;
         let admin_password_hash = std::env::var("ADMIN_PASSWORD_HASH").unwrap_or_default();
+        let database_url = std::env::var("DATABASE_URL").context("DATABASE_URL must be set")?;
 
-        validate_secrets(is_prod, &jwt_secret, &admin_password_hash)?;
+        validate_secrets(is_prod, &jwt_secret, &admin_password_hash, &database_url)?;
 
         Ok(Self {
-            database_url: std::env::var("DATABASE_URL").context("DATABASE_URL must be set")?,
+            database_url,
             jwt_secret,
             session_expiry_days: std::env::var("SESSION_EXPIRY_DAYS")
                 .unwrap_or_else(|_| "30".to_string())
@@ -141,12 +174,18 @@ mod tests {
 
     const REAL_SECRET: &str = "a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2";
     const REAL_HASH: &str = "$2y$12$abcdefghijklmnopqrstuv.wxyzABCDEFGHIJKLMNOPQRSTUVWXYZ012";
+    const REAL_DB_URL: &str = "postgres://eventsnap:7f3a9c1e5b2d8a4f@db:5432/eventsnap";
 
     #[test]
     fn prod_rejects_shipped_placeholder_secret() {
         // The exact string shipped in `.env` — >32 chars, so it must be caught by
         // the substring guard, not the length check.
-        let err = validate_secrets(true, "change_me_to_a_random_64_byte_hex_string", REAL_HASH);
+        let err = validate_secrets(
+            true,
+            "change_me_to_a_random_64_byte_hex_string",
+            REAL_HASH,
+            REAL_DB_URL,
+        );
         assert!(
             err.is_err(),
             "placeholder JWT_SECRET must be rejected in prod"
@@ -155,29 +194,108 @@ mod tests {
 
     #[test]
     fn prod_rejects_dev_sentinel_and_short_secret() {
-        assert!(validate_secrets(true, DEV_JWT_SECRET_SENTINEL, REAL_HASH).is_err());
-        assert!(validate_secrets(true, "tooshort", REAL_HASH).is_err());
+        assert!(validate_secrets(true, DEV_JWT_SECRET_SENTINEL, REAL_HASH, REAL_DB_URL).is_err());
+        assert!(validate_secrets(true, "tooshort", REAL_HASH, REAL_DB_URL).is_err());
     }
 
     #[test]
     fn prod_rejects_missing_or_placeholder_admin_hash() {
-        assert!(validate_secrets(true, REAL_SECRET, "").is_err());
-        assert!(validate_secrets(true, REAL_SECRET, "$2y$12$placeholder_replace_me").is_err());
+        assert!(validate_secrets(true, REAL_SECRET, "", REAL_DB_URL).is_err());
+        assert!(
+            validate_secrets(
+                true,
+                REAL_SECRET,
+                "$2y$12$placeholder_replace_me",
+                REAL_DB_URL
+            )
+            .is_err()
+        );
+    }
+
+    /// The stack used to come up GREEN on the database password published in the repo: this guard
+    /// covered the two secrets it was written for, and nothing anywhere looked at the Postgres
+    /// credential. README step 2 doesn't name POSTGRES_PASSWORD either, so following the
+    /// documented procedure verbatim shipped it.
+    #[test]
+    fn prod_rejects_the_shipped_placeholder_database_password() {
+        let shipped = "postgres://eventsnap:CHANGE_ME_use_a_strong_password@db:5432/eventsnap";
+        let err = validate_secrets(true, REAL_SECRET, REAL_HASH, shipped).unwrap_err();
+        assert!(
+            err.to_string().contains("DATABASE_URL"),
+            "the refusal must name DATABASE_URL, not just fail: {err}"
+        );
+        // And it must point at the initdb trap, or the operator edits .env, restarts, and lands
+        // in a permanent auth-failure loop instead.
+        assert!(
+            err.to_string().contains("POSTGRES_PASSWORD"),
+            "the refusal must name POSTGRES_PASSWORD as the other half: {err}"
+        );
+    }
+
+    /// Every problem in ONE message. Reporting them one per boot made fixing two secrets cost two
+    /// restart cycles, on a stack where Caddy waits on the unhealthy app the whole time.
+    #[test]
+    fn prod_reports_every_placeholder_at_once() {
+        let err = validate_secrets(
+            true,
+            "change_me_to_a_random_64_byte_hex_string",
+            "$2y$12$placeholder_replace_me",
+            "postgres://eventsnap:CHANGE_ME_use_a_strong_password@db:5432/eventsnap",
+        )
+        .unwrap_err()
+        .to_string();
+        for expected in ["JWT_SECRET", "ADMIN_PASSWORD_HASH", "DATABASE_URL"] {
+            assert!(err.contains(expected), "{expected} missing from: {err}");
+        }
+        assert!(
+            err.contains("3 secret(s)"),
+            "the count must match what is listed: {err}"
+        );
     }
 
     #[test]
     fn prod_accepts_real_secrets() {
-        assert!(validate_secrets(true, REAL_SECRET, REAL_HASH).is_ok());
+        assert!(validate_secrets(true, REAL_SECRET, REAL_HASH, REAL_DB_URL).is_ok());
+    }
+
+    /// A real password that happens to contain no placeholder substring must pass — including one
+    /// with URL-ish punctuation, so the guard can't be mistaken for a URL validator.
+    #[test]
+    fn prod_accepts_a_real_database_url_with_awkward_punctuation() {
+        assert!(
+            validate_secrets(
+                true,
+                REAL_SECRET,
+                REAL_HASH,
+                "postgres://eventsnap:aB3%24xY9-_.qW@db:5432/eventsnap"
+            )
+            .is_ok()
+        );
+    }
+
+    /// The e2e stack runs without APP_ENV=production, so none of this applies there — but assert
+    /// it, because a guard that tripped in e2e would be found the hard way.
+    #[test]
+    fn non_prod_ignores_a_placeholder_database_url() {
+        assert!(
+            validate_secrets(
+                false,
+                REAL_SECRET,
+                "",
+                "postgres://eventsnap:CHANGE_ME_use_a_strong_password@db:5432/eventsnap"
+            )
+            .is_ok()
+        );
     }
 
     #[test]
     fn non_prod_tolerates_dev_sentinel() {
-        assert!(validate_secrets(false, DEV_JWT_SECRET_SENTINEL, "").is_ok());
+        assert!(validate_secrets(false, DEV_JWT_SECRET_SENTINEL, "", REAL_DB_URL).is_ok());
     }
 
     #[test]
     fn non_prod_still_rejects_short_non_sentinel_secret() {
-        assert!(validate_secrets(false, "tooshort", "").is_err());
+        assert!(validate_secrets(false, "tooshort", "", REAL_DB_URL).is_err());
     }
 
     #[test]
@@ -185,9 +303,23 @@ mod tests {
         // looks_placeholder lowercases before matching — an upper/mixed-case
         // placeholder must still be rejected in prod.
         assert!(
-            validate_secrets(true, "CHANGE_ME_TO_A_RANDOM_64_BYTE_HEX_STRING", REAL_HASH).is_err()
+            validate_secrets(
+                true,
+                "CHANGE_ME_TO_A_RANDOM_64_BYTE_HEX_STRING",
+                REAL_HASH,
+                REAL_DB_URL
+            )
+            .is_err()
+        );
+        assert!(
+            validate_secrets(
+                true,
+                REAL_SECRET,
+                "$2Y$12$PLACEHOLDER_replace_me",
+                REAL_DB_URL
+            )
+            .is_err()
         );
-        assert!(validate_secrets(true, REAL_SECRET, "$2Y$12$PLACEHOLDER_replace_me").is_err());
     }
 
     #[test]
@@ -197,7 +329,7 @@ mod tests {
         const LEN_31: &str = "abcdefghijklmnopqrstuvwxyz01234";
         assert_eq!(LEN_32.len(), 32);
         assert_eq!(LEN_31.len(), 31);
-        assert!(validate_secrets(true, LEN_32, REAL_HASH).is_ok());
-        assert!(validate_secrets(true, LEN_31, REAL_HASH).is_err());
+        assert!(validate_secrets(true, LEN_32, REAL_HASH, REAL_DB_URL).is_ok());
+        assert!(validate_secrets(true, LEN_31, REAL_HASH, REAL_DB_URL).is_err());
     }
 }

backend/src/db.rs

@@ -4,17 +4,65 @@ use sqlx::postgres::PgPoolOptions;
 
 const DEFAULT_MAX_CONNECTIONS: u32 = 10;
 
+/// SQLSTATE for `invalid_password`.
+const PG_INVALID_PASSWORD: &str = "28P01";
+
+/// Turn the one connect failure with an unguessable cause into a self-explaining one.
+///
+/// `POSTGRES_PASSWORD` is honoured ONLY when Postgres initialises its data directory. Change it in
+/// `.env` afterwards and the app authenticates with the new password against a volume that still
+/// holds the old one — a permanent restart loop whose only symptom is
+/// `password authentication failed`.
+///
+/// The production secret guard makes that sequence NEARLY CERTAIN rather than rare: it stops the
+/// app on the first `docker compose up -d`, but not the `db` service in that same command, which
+/// initialises and bakes in whatever password was in `.env` at that moment. So the intended
+/// recovery — see the refusal, fix your secrets, boot again — is exactly the sequence that breaks
+/// it. Nothing in the error names the cause, and the remedy destroys data, so it is the last thing
+/// an operator should guess at.
+fn explain_auth_failure(err: &sqlx::Error) {
+    let is_auth_failure = match err {
+        sqlx::Error::Database(db) => db.code().as_deref() == Some(PG_INVALID_PASSWORD),
+        _ => false,
+    };
+    if !is_auth_failure {
+        return;
+    }
+    tracing::error!(
+        "Postgres rejected the credentials in DATABASE_URL (SQLSTATE {PG_INVALID_PASSWORD}).\n\
+         \n\
+         This almost always means POSTGRES_PASSWORD was changed AFTER the database volume was \
+         first created. Postgres applies that variable only when it initialises its data \
+         directory; editing .env and restarting does not change the stored password, so the two \
+         drift apart permanently.\n\
+         \n\
+         If the event has NOT started and you have no data worth keeping:\n\n    \
+         docker compose down -v && docker compose up -d\n\n\
+         (-v DELETES the database, the uploaded media and the exports. There is no undo.)\n\
+         \n\
+         If you DO have data: restore the old password into DATABASE_URL instead, or change the \
+         stored one with ALTER ROLE inside the running db container. Never reach for -v to fix a \
+         login problem on a live event."
+    );
+}
+
 pub async fn create_pool(database_url: &str) -> Result<PgPool> {
     let max_connections = std::env::var("DATABASE_MAX_CONNECTIONS")
         .ok()
         .and_then(|s| s.parse::<u32>().ok())
         .unwrap_or(DEFAULT_MAX_CONNECTIONS);
 
-    let pool = PgPoolOptions::new()
+    let pool = match PgPoolOptions::new()
         .max_connections(max_connections)
         .connect(database_url)
         .await
-        .context("failed to connect to database")?;
+    {
+        Ok(pool) => pool,
+        Err(e) => {
+            explain_auth_failure(&e);
+            return Err(e).context("failed to connect to database");
+        }
+    };
 
     sqlx::migrate!()
         .run(&pool)

backend/src/handlers/admin.rs

@@ -197,6 +197,23 @@ pub async fn patch_config(
                     "Wert für {key} liegt außerhalb des zulässigen Bereichs ({min}–{max})."
                 )));
             }
+            // Zero is in range and catastrophic. `quota_tolerance` is the multiplier in
+            // `free_disk * tolerance / active_uploaders`, so 0 makes every per-user limit 0 and
+            // refuses EVERY upload — mid-event, with "Du hast dein Upload-Limit für dieses Event
+            // erreicht", an error naming the wrong cause entirely. `storage_quota_enabled` is the
+            // intended off-switch.
+            //
+            // Rejecting the value rather than raising the floor: very small tolerances are
+            // legitimate (they are how a large disk is throttled down to a sensible per-guest
+            // ceiling, and how the e2e quota tests steer it — around 1e-5 on a 174 GB volume), so
+            // a floor of, say, 0.01 would forbid real configurations to prevent one typo.
+            if key_str == "quota_tolerance" && n == 0.0 {
+                return Err(AppError::BadRequest(
+                    "quota_tolerance = 0 würde jeden Upload blockieren. Zum Abschalten der \
+                     Speicher-Quote stattdessen „Speicher-Quote aktiv“ ausschalten."
+                        .into(),
+                ));
+            }
         } else if BOOL_KEYS.contains(&key_str) {
             match value.trim().to_ascii_lowercase().as_str() {
                 "true" | "false" | "1" | "0" | "yes" | "no" | "on" | "off" => {}

backend/src/services/export.rs

@@ -20,6 +20,29 @@ use crate::state::SseEvent;
 
 static VIEWER_DIR: Dir<'_> = include_dir!("$CARGO_MANIFEST_DIR/static/export-viewer");
 
+// ── Shared visibility filter ─────────────────────────────────────────────────
+
+/// The predicate that decides what lands in a keepsake, as ONE definition.
+///
+/// Two queries have to agree on it: [`query_uploads`], which selects the rows the archives are
+/// built from, and [`estimate_export_bytes`], which sizes them for the disk preflight. They used
+/// to state it separately, and the direction of drift matters — an estimate that misses rows the
+/// archive writes UNDER-reserves, which is the exact ENOSPC the preflight exists to prevent.
+///
+/// A `SRC:`-marked copy in the integration tests cannot catch that: drift means production moved
+/// and the copy didn't, so both sides of such a test sit still and it keeps passing. Sharing the
+/// fragment removes the failure by construction instead, and leaves the test doing what it is
+/// actually good at — pinning the behaviour.
+///
+/// CONTRACT: callers must alias `upload` as `u` and join `"user"` as `usr`, and bind the event id
+/// as `$1`.
+macro_rules! export_visibility_where {
+    () => {
+        "WHERE u.event_id = $1 AND u.deleted_at IS NULL
+           AND usr.uploads_hidden = FALSE AND usr.is_banned = FALSE"
+    };
+}
+
 // ── DB query rows ────────────────────────────────────────────────────────────
 
 #[derive(sqlx::FromRow)]
@@ -557,7 +580,7 @@ async fn run_zip_export_inner(
             };
             let entry_name = format!("{folder}/{date}_{name_safe}_{}.{ext}", row.id);
 
-            let builder = ZipEntryBuilder::new(entry_name.into(), Compression::Stored);
+            let builder = keepsake_entry(entry_name, Compression::Stored);
 
             // Open BEFORE writing the entry header. A missing source is skipped (the media file
             // was deleted, or its processing failed) — but it must be skipped without aborting the
@@ -950,7 +973,7 @@ async fn run_html_export_inner(
 
         // Write data.json
         {
-            let builder = ZipEntryBuilder::new("data.json".into(), Compression::Deflate);
+            let builder = keepsake_entry("data.json".into(), Compression::Deflate);
             let mut entry = zip.write_entry_stream(builder).await?;
             let mut cursor = AllowStdIo::new(std::io::Cursor::new(data_json.as_bytes()));
             fcopy(&mut cursor, &mut entry).await?;
@@ -959,7 +982,7 @@ async fn run_html_export_inner(
 
         // Write README.txt
         {
-            let builder = ZipEntryBuilder::new("README.txt".into(), Compression::Deflate);
+            let builder = keepsake_entry("README.txt".into(), Compression::Deflate);
             let mut entry = zip.write_entry_stream(builder).await?;
             let mut cursor = AllowStdIo::new(std::io::Cursor::new(README_TEXT.as_bytes()));
             fcopy(&mut cursor, &mut entry).await?;
@@ -992,7 +1015,7 @@ async fn run_html_export_inner(
             };
 
             let entry_name = format!("media/{name}");
-            let builder = ZipEntryBuilder::new(entry_name.into(), Compression::Stored);
+            let builder = keepsake_entry(entry_name, Compression::Stored);
             let mut zip_entry = zip.write_entry_stream(builder).await?;
             let mut f = src_file.compat();
             fcopy(&mut f, &mut zip_entry).await?;
@@ -1051,7 +1074,7 @@ async fn run_html_export_inner(
 // ── DB helpers ───────────────────────────────────────────────────────────────
 
 async fn query_uploads(pool: &PgPool, event_id: Uuid) -> Result<Vec<ExportUploadRow>> {
-    Ok(sqlx::query_as::<_, ExportUploadRow>(
+    Ok(sqlx::query_as::<_, ExportUploadRow>(concat!(
         "SELECT u.id, u.original_path, u.mime_type, u.caption,
                 usr.display_name AS uploader_name,
                 COUNT(DISTINCT l.user_id) AS like_count,
@@ -1059,11 +1082,12 @@ async fn query_uploads(pool: &PgPool, event_id: Uuid) -> Result<Vec<ExportUpload
          FROM upload u
          JOIN \"user\" usr ON usr.id = u.user_id
          LEFT JOIN \"like\" l ON l.upload_id = u.id
-         WHERE u.event_id = $1 AND u.deleted_at IS NULL
-           AND usr.uploads_hidden = FALSE AND usr.is_banned = FALSE
+         ",
+        export_visibility_where!(),
+        "
          GROUP BY u.id, usr.display_name
          ORDER BY u.created_at ASC",
-    )
+    ))
     .bind(event_id)
     .fetch_all(pool)
     .await?)
@@ -1267,15 +1291,16 @@ fn is_superseded_archive(
 /// downscaled to 2000px first, which only makes this estimate more conservative — the direction we
 /// want, since being wrong low means ENOSPC halfway through.
 ///
-/// Matches [`query_uploads`]' visibility filter exactly, so hidden/banned uploads aren't counted.
+/// Shares [`query_uploads`]' visibility filter via [`export_visibility_where`], so hidden/banned
+/// uploads can't be counted here but skipped there (or the reverse, which under-reserves).
 pub async fn estimate_export_bytes(pool: &PgPool, event_id: Uuid) -> Result<u64> {
-    let (bytes,): (i64,) = sqlx::query_as(
+    let (bytes,): (i64,) = sqlx::query_as(concat!(
         "SELECT COALESCE(SUM(u.original_size_bytes), 0)::bigint
            FROM upload u
            JOIN \"user\" usr ON usr.id = u.user_id
-          WHERE u.event_id = $1 AND u.deleted_at IS NULL
-            AND usr.uploads_hidden = FALSE AND usr.is_banned = FALSE",
-    )
+           ",
+        export_visibility_where!(),
+    ))
     .bind(event_id)
     .fetch_one(pool)
     .await
@@ -1527,6 +1552,36 @@ async fn maybe_broadcast_complete(
 /// double-clicking `index.html` (file://), where browsers block a cross-origin
 /// `fetch()` of a sibling `data.json` — so the data is inlined into the page.
 /// (`data.json` is still written separately for the http-served case.)
+/// Permissions stamped on every entry in both archives: `rw-r--r--`.
+///
+/// `ZipEntryBuilder::new` leaves the external file attribute at zero, and the host compatibility
+/// defaults to Unix — so every entry was written with a stored mode of **0000**. Windows Explorer
+/// ignores Unix modes and was fine, which is exactly why this survived: on Linux and macOS
+/// `unzip` faithfully applies what the archive asks for, and the guest gets a directory of files
+/// none of which they can open. `?---------` on every line of `unzip -Z`.
+///
+/// That is the keepsake — the artifact the whole event exists to produce — arriving unreadable,
+/// after distribution, with no server-side symptom at all.
+/// `S_IFREG | 0644`. The type bits are included because the mode is written whole into the high
+/// half of the external file attribute: without them extractors see a file of type "unknown"
+/// (`unzip -Z` renders `?rw-r--r--`), which works but is not what the archive means to say.
+const KEEPSAKE_ENTRY_MODE: u16 = 0o100_644;
+
+/// Build a ZIP entry for the keepsake. ALL entries in both archives go through here so the mode
+/// can't be forgotten at one of the six call sites.
+fn keepsake_entry(name: String, compression: Compression) -> ZipEntryBuilder {
+    ZipEntryBuilder::new(name.into(), compression).unix_permissions(KEEPSAKE_ENTRY_MODE)
+}
+
+/// Escape a JSON payload for inlining inside a `<script>` element.
+///
+/// See the call site in [`write_viewer_with_data`] for why this is every `<` and not just `</`.
+/// Kept separate so the property that matters — no `<` survives, and the value still decodes to
+/// the original — can be asserted without building a ZIP.
+fn escape_json_for_script(data_json: &str) -> String {
+    data_json.replace('<', "\\u003c")
+}
+
 async fn write_viewer_with_data(
     dir: &include_dir::Dir<'_>,
     zip: &mut ZipFileWriter<tokio::fs::File>,
@@ -1538,8 +1593,31 @@ async fn write_viewer_with_data(
         if path == "index.html" {
             let html = std::str::from_utf8(file.contents())
                 .context("export-viewer index.html is not valid UTF-8")?;
-            // Escape `</` so a caption containing `</script>` can't break out of the tag.
-            let safe = data_json.replace("</", "<\\/");
+            // Escape EVERY `<`, not just `</`.
+            //
+            // `</` -> `<\/` stops the obvious break-out (`</script><img onerror=…>`) and is inert
+            // against XSS. It does not stop the caption steering the HTML TOKENIZER. A caption
+            // containing `<!--<script` with no later `-->` puts the parser into
+            // script-data-double-escaped state; from there the template's own `</script>` only
+            // steps back to script-data-escaped instead of closing the element, and the rest of the
+            // document — including the viewer bundle — is swallowed as script data. Nothing
+            // executes and nothing leaks; `window.__EXPORT_DATA__` is simply never assigned and the
+            // keepsake opens blank.
+            //
+            // That failure is silent and POST-DISTRIBUTION: the export succeeds, the ZIP is
+            // well-formed, the job writes `done`, /export/status is green, and the host hands out a
+            // file that only fails when a guest double-clicks index.html — in every copy, with no
+            // way to fix it after the fact. Reachable from any guest-authored caption or comment,
+            // since both are embedded in the viewer.
+            //
+            // `<` never appears in JSON structural syntax — only inside string values — so a global
+            // replace is sound, and `<` is valid in both JSON and a JS string literal. One
+            // rule covers `</script`, `<!--` and `<script` together, which is the point: the
+            // previous escape was named for the single case it did handle.
+            //
+            // NOTE this is deliberately only for the INLINED copy. `data.json` is written
+            // separately, in no HTML context, and must stay literal.
+            let safe = escape_json_for_script(data_json);
             // Match the live app's colour theme: inject the same `:root:root{…}` override
             // the app builds at runtime so a rose/sage/custom event exports a rose/sage
             // keepsake (not the embedded default gold). The CSS is generated purely from
@@ -1553,13 +1631,13 @@ async fn write_viewer_with_data(
                 Some(idx) => format!("{}{}{}", &html[..idx], head_inject, &html[idx..]),
                 None => format!("{head_inject}{html}"),
             };
-            let builder = ZipEntryBuilder::new(path.into(), Compression::Deflate);
+            let builder = keepsake_entry(path, Compression::Deflate);
             let mut entry = zip.write_entry_stream(builder).await?;
             let mut cursor = AllowStdIo::new(std::io::Cursor::new(injected.as_bytes()));
             fcopy(&mut cursor, &mut entry).await?;
             entry.close().await?;
         } else {
-            let builder = ZipEntryBuilder::new(path.into(), Compression::Deflate);
+            let builder = keepsake_entry(path, Compression::Deflate);
             let mut entry = zip.write_entry_stream(builder).await?;
             let mut cursor = AllowStdIo::new(std::io::Cursor::new(file.contents()));
             fcopy(&mut cursor, &mut entry).await?;
@@ -1790,6 +1868,62 @@ mod tests {
         }
     }
 
+    /// Every `<` is escaped, whatever it is part of.
+    ///
+    /// PREVENTS the regression to `</` -> `<\\/`, which is named for the one case it handles.
+    /// `<!--<script` with no later `-->` drives the HTML tokenizer into
+    /// script-data-double-escaped state, where the template's own `</script>` no longer closes
+    /// the element — the viewer bundle is swallowed as script data, `__EXPORT_DATA__` is never
+    /// assigned, and the keepsake opens blank in every copy the host has already handed out.
+    #[test]
+    fn no_left_angle_bracket_survives_inlining() {
+        for payload in [
+            r#"{"caption":"<!--<script"}"#,
+            r#"{"caption":"</script><img src=x onerror=alert(1)>"}"#,
+            r#"{"caption":"<!--"}"#,
+            r#"{"caption":"<script>"}"#,
+            r#"{"caption":"a < b"}"#,
+        ] {
+            let escaped = escape_json_for_script(payload);
+            assert!(
+                !escaped.contains('<'),
+                "a surviving `<` can still steer the tokenizer: {escaped}"
+            );
+        }
+    }
+
+    /// The escape must not change what the viewer READS — it is a transport encoding, not a
+    /// sanitiser. A caption is guest-authored text that has to render back exactly.
+    #[test]
+    fn the_payload_still_decodes_to_the_original_value() {
+        // `<` appears only inside JSON string values, never in structural syntax, so a global
+        // replace is sound — this is the assertion that says so.
+        for caption in [
+            "<!--<script",
+            "</script><img src=x onerror=alert(1)>",
+            "a < b und c > d",
+            "ganz normale Bildunterschrift",
+            "Herz <3",
+        ] {
+            let json = serde_json::json!({ "posts": [{ "caption": caption }] }).to_string();
+            let escaped = escape_json_for_script(&json);
+            let back: serde_json::Value =
+                serde_json::from_str(&escaped).expect("the escaped form must still be valid JSON");
+            assert_eq!(
+                back["posts"][0]["caption"].as_str(),
+                Some(caption),
+                "the caption must survive the round trip unchanged"
+            );
+        }
+    }
+
+    /// Nothing else in the document is touched.
+    #[test]
+    fn a_payload_with_no_angle_brackets_is_unchanged() {
+        let json = r#"{"posts":[{"caption":"schönes Foto"}]}"#;
+        assert_eq!(escape_json_for_script(json), json);
+    }
+
     #[test]
     fn a_lone_armed_job_reserves_for_one_archive() {
         // A ViewerOnly regeneration re-arms only the HTML half — reserving for two would refuse

backend/tests/common/mod.rs

@@ -293,6 +293,10 @@ pub async fn set_user_moderation(pool: &PgPool, user_id: Uuid, banned: bool, hid
 
 /// SRC: `services/export.rs::query_uploads` — the visibility filter, verbatim, projected down to
 /// `(id, original_size_bytes)`. This is the row set that ACTUALLY lands in the archives.
+///
+/// Production builds this WHERE from `export_visibility_where!()`, shared with
+/// `estimate_export_bytes`. A copy here can pin the behaviour but CANNOT detect production moving
+/// away from it — that is what sharing the fragment is for, not this.
 pub async fn export_visible_uploads(pool: &PgPool, event_id: Uuid) -> Vec<(Uuid, i64)> {
     sqlx::query_as(
         "SELECT u.id, u.original_size_bytes
@@ -309,7 +313,9 @@ pub async fn export_visible_uploads(pool: &PgPool, event_id: Uuid) -> Vec<(Uuid,
     .expect("export_visible_uploads")
 }
 
-/// SRC: `services/export.rs::estimate_export_bytes` — verbatim.
+/// SRC: `services/export.rs::estimate_export_bytes` — verbatim. Same caveat as above: production
+/// shares its WHERE with `query_uploads` via `export_visibility_where!()`, so these two copies
+/// agreeing proves the behaviour, not the absence of drift.
 pub async fn estimate_export_bytes(pool: &PgPool, event_id: Uuid) -> i64 {
     let (bytes,): (i64,) = sqlx::query_as(
         "SELECT COALESCE(SUM(u.original_size_bytes), 0)::bigint

backend/tests/export_preflight.rs

@@ -16,10 +16,18 @@
 //!
 //! What these tests pin is the ESTIMATE — the part that decides. The arithmetic on top of it lives
 //! in `services/export.rs`'s unit tests; the filesystem selection lives in `is_superseded_archive`.
-//! The risk here is drift: if `query_uploads` ever gains or loses a visibility predicate and
-//! `estimate_export_bytes` doesn't, the preflight silently sizes the wrong gallery. So rather than
-//! restating the filter, these assert the estimate against the row set the archive actually
-//! contains.
+//!
+//! ON DRIFT, precisely, because it is easy to overclaim here. The hazard is that `query_uploads`
+//! (which selects the rows the archives are built from) and `estimate_export_bytes` (which sizes
+//! them) could disagree — and an estimate missing rows the archive writes UNDER-reserves, the one
+//! direction that reintroduces the ENOSPC. **These tests cannot catch that**, and neither can any
+//! test in this harness: both sides here are `SRC:`-marked hand-copies in `tests/common/mod.rs`,
+//! so if production moved and the copies didn't, they would sit still and keep passing.
+//!
+//! That is fixed where it can be — the two queries now share one `export_visibility_where!()`
+//! fragment in `services/export.rs`, so they cannot diverge by construction. What is left for
+//! these tests is what the convention is genuinely good at: pinning the BEHAVIOUR, so a change
+//! that deliberately alters the filter has to come here and say so.
 
 mod common;
 
@@ -29,9 +37,10 @@ use sqlx::PgPool;
 /// The estimate must equal the sum over EXACTLY the rows `query_uploads` returns — computed from
 /// that row set, not from a restatement of its WHERE clause.
 ///
-/// PREVENTS: the two queries drifting apart. An estimate that counts rows the archive skips is
-/// merely pessimistic; one that MISSES rows the archive writes under-reserves, which is the whole
-/// failure being guarded against.
+/// PINS: which uploads the preflight is allowed to count. Each excluded row below is excluded by a
+/// DIFFERENT predicate, so a change that drops or weakens any one of them fails here and has to be
+/// argued for. (It does not detect production drifting away from these copies — see the file
+/// header; `export_visibility_where!()` is what makes that impossible.)
 #[sqlx::test]
 async fn the_estimate_sums_exactly_the_rows_the_archive_will_contain(pool: PgPool) {
     let event_id = seed_event(&pool, "wedding").await;

e2e/specs/05-admin/config.spec.ts

@@ -68,6 +68,40 @@ test.describe('Admin — config API', () => {
     expect(cfg.privacy_note).toBe(note);
     await api.patchConfig(adminToken, { privacy_note: '' });
   });
+  test('quota_tolerance = 0 is rejected, with a pointer to the real off-switch', async ({
+    api,
+    adminToken,
+  }) => {
+    // Zero is inside the documented 0–1 range and catastrophic: the per-user limit is
+    // `free_disk * tolerance / active_uploaders`, so 0 refuses EVERY upload — mid-event, with
+    // "Du hast dein Upload-Limit für dieses Event erreicht", which names the wrong cause
+    // entirely. `storage_quota_enabled` is what an admin reaching for an off-switch wants.
+    const res = await fetch(
+      (process.env.E2E_FRONTEND_URL ?? 'http://localhost:3101') + '/api/v1/admin/config',
+      {
+        method: 'PATCH',
+        headers: { Authorization: `Bearer ${adminToken}`, 'Content-Type': 'application/json' },
+        body: JSON.stringify({ quota_tolerance: '0' }),
+      }
+    );
+    expect(res.status).toBe(400);
+    expect(
+      (await res.text()).toLowerCase(),
+      'the error must name the switch the admin actually wanted'
+    ).toContain('speicher-quote');
+
+    // The value is untouched — validation fully precedes any write.
+    expect((await api.getConfig(adminToken)).quota_tolerance).toBe('0.75');
+  });
+
+  test('a very small quota_tolerance is still accepted', async ({ api, adminToken }) => {
+    // The mirror. Rejecting 0 must not become a floor: small tolerances are how a large disk is
+    // throttled to a sensible per-guest ceiling, and how the quota specs steer it (~1e-5 on a
+    // 174 GB volume). A floor of 0.01 would forbid real configurations to prevent one typo.
+    await api.patchConfig(adminToken, { quota_tolerance: '0.00001' });
+    expect((await api.getConfig(adminToken)).quota_tolerance).toBe('0.00001');
+    await api.patchConfig(adminToken, { quota_tolerance: '0.75' });
+  });
 });
 
 test.describe('Admin — stats', () => {

e2e/specs/06-export/archive-permissions.spec.ts

@@ -0,0 +1,103 @@
+/**
+ * Regression guard — the keepsake extracts to files a guest can actually open.
+ *
+ * `ZipEntryBuilder::new` leaves the external file attribute at zero, and async_zip's host
+ * compatibility defaults to Unix — so every entry in BOTH archives was written with a stored mode
+ * of 0000. `unzip -Z` showed `?---------` on every line.
+ *
+ * Windows Explorer ignores Unix modes, which is exactly why this survived. On Linux and macOS,
+ * `unzip` faithfully applies what the archive asks for, and the guest gets a folder of photos none
+ * of which they can open — plus an index.html the browser refuses with ERR_ACCESS_DENIED.
+ *
+ * Unconditional: it affected every keepsake ever produced, no hostile input required. And it is
+ * invisible server-side — the export succeeds, the ZIP is well-formed, the job writes `done`,
+ * /export/status is green. The only way to see it is to extract the real artifact and try to read
+ * it, which is what this does.
+ *
+ * Found while chasing an unrelated ERR_ACCESS_DENIED that looked like a Playwright quirk.
+ */
+import { test, expect } from '../../fixtures/test';
+import { execFileSync } from 'node:child_process';
+import { mkdtempSync, writeFileSync, rmSync, readFileSync, statSync, readdirSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { seedUpload } from '../../helpers/seed';
+import { BASE } from '../../helpers/env';
+
+/** Walk every file under `dir`, ignoring the archives we dropped there ourselves. */
+function walk(dir: string, skip: string[] = []): string[] {
+  return readdirSync(dir, { withFileTypes: true }).flatMap((e) => {
+    const p = join(dir, e.name);
+    if (e.isDirectory()) return walk(p, skip);
+    return skip.includes(e.name) ? [] : [p];
+  });
+}
+
+test.describe('Export — the archives extract to readable files', () => {
+  test('every entry in both keepsake archives is owner-readable', async ({ host, guest, db }) => {
+    test.setTimeout(120_000);
+    const bearer = { Authorization: `Bearer ${host.jwt}` };
+
+    const g = await guest('Archivist');
+    const id = await seedUpload(g.jwt, { caption: 'ein Foto' });
+    await expect.poll(() => db.compressionStatus(id), { timeout: 30_000 }).toBe('done');
+
+    expect(
+      (await fetch(`${BASE}/api/v1/host/gallery/release`, { method: 'POST', headers: bearer }))
+        .status
+    ).toBe(204);
+
+    await expect
+      .poll(
+        async () => {
+          const res = await fetch(`${BASE}/api/v1/export/status`, { headers: bearer });
+          const s = await res.json();
+          return s.zip?.status === 'done' && s.html?.status === 'done';
+        },
+        { timeout: 90_000, intervals: [500] }
+      )
+      .toBe(true);
+
+    for (const kind of ['zip', 'html'] as const) {
+      const ticketRes = await fetch(`${BASE}/api/v1/export/ticket`, {
+        method: 'POST',
+        headers: bearer,
+      });
+      const { ticket } = (await ticketRes.json()) as { ticket: string };
+      const dl = await fetch(`${BASE}/api/v1/export/${kind}?ticket=${encodeURIComponent(ticket)}`);
+      expect(dl.status, `downloading the ${kind} archive`).toBe(200);
+
+      const dir = mkdtempSync(join(tmpdir(), `eventsnap-perms-${kind}-`));
+      try {
+        const zipPath = join(dir, 'archive.zip');
+        writeFileSync(zipPath, Buffer.from(await dl.arrayBuffer()));
+
+        // The mode as STORED in the archive — this is what a guest's unzip will apply. Reading it
+        // from the central directory catches the defect even on a filesystem that would mask it.
+        const listing = execFileSync('unzip', ['-Z', zipPath], { encoding: 'utf8' });
+        const modes = listing
+          .split('\n')
+          .filter((l) => /^[?d-][rwx-]{9}\s/.test(l))
+          .map((l) => l.slice(0, 10));
+        expect(modes.length, `${kind}: no entries listed`).toBeGreaterThan(0);
+        for (const m of modes) {
+          expect(m, `${kind}: an entry is stored mode ${m} — the guest cannot open it`).toMatch(
+            /^.r[w-]-/
+          );
+        }
+
+        // And extraction really does produce readable files.
+        execFileSync('unzip', ['-qo', zipPath, '-d', dir]);
+        const files = walk(dir, ['archive.zip']);
+        expect(files.length, `${kind}: nothing extracted`).toBeGreaterThan(0);
+        for (const f of files) {
+          expect(statSync(f).mode & 0o400, `${f} is not owner-readable`).toBeTruthy();
+          // The assertion that matters to a guest: the bytes actually come out.
+          expect(() => readFileSync(f)).not.toThrow();
+        }
+      } finally {
+        rmSync(dir, { recursive: true, force: true });
+      }
+    }
+  });
+});

e2e/specs/06-export/viewer-caption-injection.spec.ts

@@ -0,0 +1,125 @@
+/**
+ * Regression guard — a guest-authored caption cannot brick the offline keepsake.
+ *
+ * The viewer's data is inlined as `<script>window.__EXPORT_DATA__={…};</script>` (it must be:
+ * guests open index.html over file://, where a cross-origin fetch of a sibling data.json is
+ * blocked). Captions and comments are guest text and land in that payload.
+ *
+ * The escape used to be `</` → `<\/`. Against XSS that holds — `</script><img src=x onerror=…>`
+ * round-trips inert. It does NOT stop the caption steering the HTML TOKENIZER: `<!--<script` with
+ * no later `-->` drives the parser into script-data-double-escaped state, where the template's own
+ * `</script>` steps back to script-data-escaped instead of closing the element. Everything after —
+ * including the viewer bundle — is swallowed as script data. Nothing executes and nothing leaks;
+ * `__EXPORT_DATA__` is never assigned and the keepsake renders blank.
+ *
+ * What makes it worth a browser-level test rather than a unit test alone: the failure is SILENT and
+ * POST-DISTRIBUTION. The export succeeds, the ZIP is well-formed, the job writes `done`,
+ * /export/status is green, and the host hands out a file that only fails when a guest
+ * double-clicks it — in every copy, unfixably. It is not visible by reading the escape. It is only
+ * visible by running a real parser over the real artifact, which is what this does: release, pull
+ * the actual Memories.zip, extract index.html, open it over file:// in Chromium, and assert the
+ * viewer actually booted.
+ *
+ * The near-miss worth recording: `<!--<script>alert(1)</script>-->` comes back CLEAN, because the
+ * trailing `-->` returns the parser to script-data state. A probe using the terminated form
+ * quietly repairs the very thing it is testing for. Only the unterminated variant exposes it.
+ */
+import { test, expect } from '../../fixtures/test';
+import { execFileSync } from 'node:child_process';
+import { mkdtempSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { seedUpload } from '../../helpers/seed';
+import { BASE } from '../../helpers/env';
+
+/** Unterminated on purpose — see the header. The terminated form self-repairs. */
+const TOKENIZER_PAYLOAD = '<!--<script';
+/** The classic break-out. Already handled, kept so the fix can never regress on it. */
+const BREAKOUT_PAYLOAD = '</script><img src=x onerror=window.__XSS__=1>';
+
+test.describe('Export — a caption cannot brick the keepsake viewer', () => {
+  test('the exported viewer boots with a tokenizer-hostile caption in it', async ({
+    page,
+    host,
+    guest,
+    db,
+  }) => {
+    test.setTimeout(120_000);
+    const bearer = { Authorization: `Bearer ${host.jwt}` };
+
+    const g = await guest('Trickster');
+    const a = await seedUpload(g.jwt, { caption: TOKENIZER_PAYLOAD });
+    const b = await seedUpload(g.jwt, { caption: BREAKOUT_PAYLOAD });
+    for (const id of [a, b]) {
+      await expect.poll(() => db.compressionStatus(id), { timeout: 30_000 }).toBe('done');
+    }
+
+    expect(
+      (await fetch(`${BASE}/api/v1/host/gallery/release`, { method: 'POST', headers: bearer }))
+        .status
+    ).toBe(204);
+
+    await expect
+      .poll(
+        async () => {
+          const res = await fetch(`${BASE}/api/v1/export/status`, { headers: bearer });
+          return (await res.json()).html?.status;
+        },
+        { timeout: 90_000, intervals: [500] }
+      )
+      .toBe('done');
+
+    const ticketRes = await fetch(`${BASE}/api/v1/export/ticket`, {
+      method: 'POST',
+      headers: bearer,
+    });
+    const { ticket } = (await ticketRes.json()) as { ticket: string };
+    const dl = await fetch(`${BASE}/api/v1/export/html?ticket=${encodeURIComponent(ticket)}`);
+    expect(dl.status).toBe(200);
+
+    const dir = mkdtempSync(join(tmpdir(), 'eventsnap-viewer-'));
+    try {
+      const zipPath = join(dir, 'Memories.zip');
+      writeFileSync(zipPath, Buffer.from(await dl.arrayBuffer()));
+      // Extract the WHOLE archive: index.html pulls in the viewer's own JS/CSS, and the point of
+      // this test is that those later resources are still reachable by the parser.
+      execFileSync('unzip', ['-qo', zipPath, '-d', dir]);
+
+      // file://, not http://. That is how a guest actually opens the keepsake, and it is the
+      // whole reason the data is inlined rather than fetched from a sibling data.json.
+      let xss = false;
+      page.on('dialog', (d) => {
+        xss = true;
+        void d.dismiss();
+      });
+      await page.goto('file://' + join(dir, 'index.html'));
+
+      // 1. The payload was assigned at all. This is the assertion that fails on the old escape —
+      //    the second script block is never reached, so the global stays undefined.
+      const captions = await page.evaluate(() => {
+        const d = (window as unknown as { __EXPORT_DATA__?: { posts?: { caption?: string }[] } })
+          .__EXPORT_DATA__;
+        return d?.posts?.map((p) => p.caption ?? '') ?? null;
+      });
+      expect(captions, '__EXPORT_DATA__ was never assigned — the viewer is bricked').not.toBeNull();
+
+      // 2. The captions survived verbatim. The escape is a transport encoding, not a sanitiser:
+      //    a guest's text has to come back exactly, or we have silently rewritten their words.
+      expect(captions).toContain(TOKENIZER_PAYLOAD);
+      expect(captions).toContain(BREAKOUT_PAYLOAD);
+
+      // 3. And nothing executed.
+      expect(
+        await page.evaluate(() => (window as unknown as { __XSS__?: number }).__XSS__ === 1),
+        'the caption must be inert, not merely non-fatal'
+      ).toBe(false);
+      expect(xss).toBe(false);
+
+      // 4. The viewer actually rendered — the whole document parsed, not just the head. If the
+      //    tokenizer had swallowed the bundle, the body would be empty of viewer output.
+      await expect(page.locator('body')).not.toBeEmpty();
+    } finally {
+      rmSync(dir, { recursive: true, force: true });
+    }
+  });
+});