feat(e2e): Playwright suite — 134 tests across 9 spec areas + UA matrix

Adds an end-to-end Playwright test suite under e2e/ that spins up an
isolated docker-compose stack (Postgres :55432, Caddy :3101, backend with
EVENTSNAP_TEST_MODE=1, SvelteKit adapter-node frontend) and exercises the
SvelteKit app against the real Rust backend.

Phase 1 — happy paths covering every documented USER_JOURNEYS.md flow:
  01-auth/      join, recover, admin login, leave event, PIN lockout
  02-upload/    gallery picker (API path), rate-limit + admin toggle
  03-feed/      like/comment SSE, filters, SSE reconnect on visibility
  04-host/      event lock API, ban/unban, promote
  05-admin/     config validation, foundational authz guards, stats
  06-export/    /export status + download stub
  __smoke/      cross-UA happy-path (runs on every UA project)

Phase 2 — adversarial + browser chaos:
  07-adversarial/  XSS payloads (6 × display name path), SQLi shapes,
                   length / encoding / RTL override / NUL byte;
                   file-upload boundaries (ELF body claimed as JPEG,
                   oversize vs max_image_size_mb, zero-byte, NUL
                   filename, path-traversal, SVG-with-script);
                   JWT alg:none, signature/payload tamper, expired
                   session, PIN brute-force (serial + parallel),
                   admin password brute-force; deep authz (cross-user
                   delete, banned user across like/comment/feed-read,
                   host→admin escalation); small-scale DDoS (20× /join,
                   10MB comment body, 10 concurrent SSE).
  08-browser-chaos/ localStorage / sessionStorage / cookie purge,
                    IndexedDB drop mid-session, offline → reconnect,
                    slow-3G, 503 flakes, 429 with no retry storm,
                    multi-tab same/different user, no-JS, hostile CSS,
                    clock skew ±1h / -2d, localStorage quota exhausted.

Phase 3 — mobile gestures (runs only on chromium-mobile / Pixel 7):
  09-mobile/    touch-target ≥44px audit, env(safe-area-inset-bottom)
                structural check, long-press (FeedListCard → ContextSheet,
                quick-tap negation, click-suppression), double-tap
                (feed card like + lightbox heart-burst, via synthetic
                pointer events to bypass the first-tap-fires-click trap),
                viewport reflow (portrait/landscape/narrow/phablet),
                plus fixme stubs documenting planned gestures (swipe
                lightbox L/R, swipe-down dismiss, pull-to-refresh,
                long-press-comment).

Cross-UA matrix (chromium-engine projects run @smoke only):
  chromium-pixel7, chromium-galaxy-s22, samsung-internet (Samsung UA
  emulation on Galaxy viewport), edge-android, plus webkit-iphone,
  chrome-ios, firefox-android, firefox-desktop — the latter four need
  libavif16 on the host (Playwright dep) but the configs are in place.

Infrastructure:
  - fixtures/test.ts central test.extend (api, db, adminToken, guest,
    host, signIn). Per-test DB truncate via the dev-only POST
    /admin/__truncate route, gated by EVENTSNAP_TEST_MODE=1.
  - helpers/sse-listener.ts, helpers/upload-client.ts (Node-side
    multipart for adversarial file-upload tests + JPEG/PNG/ELF magic
    constants), helpers/touch.ts (longPress / doubleTap / swipe /
    inlineStyle / computedStyle).
  - 10 page objects covering every route + UploadSheet/Lightbox.
  - global-setup waits for /health, logs in admin, disables every
    rate-limit and quota toggle.
  - .github/workflows/e2e.yml: PR check runs chromium-desktop + the
    smoke matrix in parallel, uploads playwright-report/ and traces on
    failure.

Findings the suite surfaces as live `[finding]` warnings (not silenced):
  1. /admin/login has no rate-limit or lockout (bcrypt cost only).
  2. PIN-attempt counter races under parallel /recover requests.
  3. Zero-byte uploads pass /api/v1/upload.
  4. SVG-with-script can pass the magic-byte check (consider CSP +
     X-Content-Type-Options on /media/*).

Stack-internal docs live in e2e/README.md (UA tier table, Samsung
Internet escalation tiers A/B/C, debugging tips, roadmap).

Final tally: 134 passed / 0 failed / 9 skipped (test.fixme stubs for
not-yet-shipped gestures and one UI-upload-flow investigation).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

e2e/fixtures/db.ts

@@ -0,0 +1,84 @@
+/**
+ * Direct PostgreSQL escape hatch for setting up states the public API doesn't
+ * expose — e.g. forcing a user into the locked-PIN state to assert the 429
+ * recovery path, or expiring sessions for chaos tests.
+ *
+ * Most tests should NOT use this: prefer `ApiClient` so the tests exercise
+ * the same code paths real users do. Reach for direct SQL only when the API
+ * can't get you where you need to go.
+ */
+import { Client } from 'pg';
+
+const CONN = {
+  host: process.env.E2E_DB_HOST ?? 'localhost',
+  port: Number(process.env.E2E_DB_PORT ?? '55432'),
+  user: process.env.E2E_DB_USER ?? 'eventsnap_test',
+  password: process.env.E2E_DB_PASSWORD ?? 'eventsnap_test',
+  database: process.env.E2E_DB_NAME ?? 'eventsnap_test',
+};
+
+async function withClient<T>(fn: (c: Client) => Promise<T>): Promise<T> {
+  const client = new Client(CONN);
+  await client.connect();
+  try {
+    return await fn(client);
+  } finally {
+    await client.end();
+  }
+}
+
+export const db = {
+  async lockUserPin(userId: string, minutesFromNow = 15) {
+    await withClient((c) =>
+      c.query(
+        `UPDATE "user" SET pin_locked_until = NOW() + ($2 || ' minutes')::interval, failed_pin_attempts = 3 WHERE id = $1`,
+        [userId, String(minutesFromNow)]
+      )
+    );
+  },
+
+  async expireSession(userId: string) {
+    await withClient((c) =>
+      c.query(`UPDATE session SET expires_at = NOW() - interval '1 hour' WHERE user_id = $1`, [userId])
+    );
+  },
+
+  async setUploadCompressionStatus(uploadId: string, status: 'pending' | 'processing' | 'done' | 'failed') {
+    await withClient((c) =>
+      c.query(`UPDATE upload SET compression_status = $2 WHERE id = $1`, [uploadId, status])
+    );
+  },
+
+  async countUploadsForUser(userId: string): Promise<number> {
+    return withClient(async (c) => {
+      const r = await c.query<{ count: string }>(
+        `SELECT COUNT(*)::text AS count FROM upload WHERE user_id = $1 AND deleted_at IS NULL`,
+        [userId]
+      );
+      return Number(r.rows[0].count);
+    });
+  },
+
+  async setExportReleased(slug: string, released: boolean) {
+    await withClient((c) =>
+      c.query(`UPDATE event SET export_released_at = $2 WHERE slug = $1`, [
+        slug,
+        released ? new Date() : null,
+      ])
+    );
+  },
+
+  /** Insert a pre-baked export job row to skip the (slow) real compression path. */
+  async fakeExportJob(eventSlug: string, type: 'zip' | 'html', status: 'pending' | 'running' | 'done') {
+    await withClient(async (c) => {
+      const ev = await c.query<{ id: string }>(`SELECT id FROM event WHERE slug = $1`, [eventSlug]);
+      if (ev.rows.length === 0) throw new Error(`No event with slug ${eventSlug}`);
+      await c.query(
+        `INSERT INTO export_job (event_id, type, status, progress_pct, completed_at)
+         VALUES ($1, $2::export_type, $3::export_status, $4, $5)
+         ON CONFLICT (event_id, type) DO UPDATE SET status = EXCLUDED.status, progress_pct = EXCLUDED.progress_pct`,
+        [ev.rows[0].id, type, status, status === 'done' ? 100 : 0, status === 'done' ? new Date() : null]
+      );
+    });
+  },
+};