feat(history): report personal new-chapter count on read-progress list

Add `new_chapters_count` to each `GET /me/read-progress` item: how many
chapters sit past the reader's last-read chapter, computed by a correlated
subquery on chapter number. It is 0 when the reader is caught up, and 0
when the last-read chapter is unknown (manga-level progress or a deleted
chapter) so we never over-claim. (manga_id, number) is non-unique, so this
counts positions past the reader rather than distinct files.

Backs the personal "new since last read" indicator on the upcoming
Continue-reading shelf. Tests cover the mid-series, caught-up, and
no-read-chapter cases.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/Cargo.lock

@@ -1558,7 +1558,7 @@ checksum = "c41e0c4fef86961ac6d6f8a82609f55f31b05e4fce149ac5710e439df7619ba4"
 
 [[package]]
 name = "mangalord"
-version = "0.94.0"
+version = "0.94.1"
 dependencies = [
  "anyhow",
  "argon2",

backend/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mangalord"
-version = "0.94.1"
+version = "0.95.0"
 edition = "2021"
 default-run = "mangalord"
 

backend/src/domain/read_progress.rs

@@ -26,6 +26,12 @@ pub struct ReadProgressSummary {
     pub chapter_number: Option<i32>,
     pub page: i32,
     pub updated_at: DateTime<Utc>,
+    /// How many chapters sit past the reader's last-read chapter (by
+    /// chapter number) — a personal "new since you last read" count.
+    /// `0` when the reader is caught up or when `chapter_number` is
+    /// unknown (manga-level progress or a deleted chapter), so we never
+    /// claim chapters are new when we can't place the reader.
+    pub new_chapters_count: i64,
 }
 
 /// Returned by `GET /me/read-progress/:manga_id`. Same shape as

backend/src/repo/read_progress.rs

@@ -132,7 +132,21 @@ pub async fn list_for_user(
                rp.chapter_id,
                c.number            AS chapter_number,
                rp.page,
-               rp.updated_at
+               rp.updated_at,
+               -- Personal "new since last read": chapters numbered past the
+               -- reader's last-read chapter. `c.number` is NULL for
+               -- manga-level progress or a deleted chapter, in which case
+               -- the guard yields 0 rather than counting every chapter.
+               -- (manga_id, number) is non-unique — translations share a
+               -- number — so this counts positions past the reader, not
+               -- distinct files.
+               COALESCE((
+                   SELECT count(*)
+                     FROM chapters c2
+                    WHERE c2.manga_id = rp.manga_id
+                      AND c.number IS NOT NULL
+                      AND c2.number > c.number
+               ), 0)               AS new_chapters_count
           FROM read_progress rp
           JOIN mangas m ON m.id = rp.manga_id
           LEFT JOIN chapters c ON c.id = rp.chapter_id

backend/tests/api_history.rs

@@ -164,6 +164,84 @@ async fn list_is_per_user_only(pool: PgPool) {
     assert_eq!(body["items"], json!([]));
 }
 
+#[sqlx::test(migrations = "./migrations")]
+async fn list_reports_new_chapters_since_last_read(pool: PgPool) {
+    let h = common::harness(pool);
+    let (_, cookie) = common::register_user(&h.app).await;
+    let manga_id = common::seed_manga_via_api(&h.app, &cookie, "Berserk").await;
+    // Three chapters exist; the reader is on chapter 1, so chapters 2 and
+    // 3 are "new since last read".
+    let ch1 = seed_chapter(&h.app, &cookie, manga_id, 1).await;
+    let _ = seed_chapter(&h.app, &cookie, manga_id, 2).await;
+    let _ = seed_chapter(&h.app, &cookie, manga_id, 3).await;
+    let _ = upsert_progress(
+        &h.app,
+        &cookie,
+        json!({ "manga_id": manga_id.to_string(), "chapter_id": ch1, "page": 1 }),
+    )
+    .await;
+
+    let resp = h
+        .app
+        .clone()
+        .oneshot(common::get_with_cookie("/api/v1/me/read-progress", &cookie))
+        .await
+        .unwrap();
+    let body = common::body_json(resp).await;
+    assert_eq!(body["items"][0]["new_chapters_count"], 2);
+}
+
+#[sqlx::test(migrations = "./migrations")]
+async fn list_new_chapters_count_is_zero_at_latest_chapter(pool: PgPool) {
+    let h = common::harness(pool);
+    let (_, cookie) = common::register_user(&h.app).await;
+    let manga_id = common::seed_manga_via_api(&h.app, &cookie, "Berserk").await;
+    let _ = seed_chapter(&h.app, &cookie, manga_id, 1).await;
+    let ch2 = seed_chapter(&h.app, &cookie, manga_id, 2).await;
+    // Caught up to the last chapter → nothing newer.
+    let _ = upsert_progress(
+        &h.app,
+        &cookie,
+        json!({ "manga_id": manga_id.to_string(), "chapter_id": ch2, "page": 1 }),
+    )
+    .await;
+
+    let resp = h
+        .app
+        .clone()
+        .oneshot(common::get_with_cookie("/api/v1/me/read-progress", &cookie))
+        .await
+        .unwrap();
+    let body = common::body_json(resp).await;
+    assert_eq!(body["items"][0]["new_chapters_count"], 0);
+}
+
+#[sqlx::test(migrations = "./migrations")]
+async fn list_new_chapters_count_is_zero_without_a_read_chapter(pool: PgPool) {
+    let h = common::harness(pool);
+    let (_, cookie) = common::register_user(&h.app).await;
+    let manga_id = common::seed_manga_via_api(&h.app, &cookie, "Berserk").await;
+    let _ = seed_chapter(&h.app, &cookie, manga_id, 1).await;
+    let _ = seed_chapter(&h.app, &cookie, manga_id, 2).await;
+    // Progress recorded without a chapter (manga-level) — we can't place
+    // the reader among the chapters, so we don't claim any are "new".
+    let _ = upsert_progress(
+        &h.app,
+        &cookie,
+        json!({ "manga_id": manga_id.to_string(), "page": 1 }),
+    )
+    .await;
+
+    let resp = h
+        .app
+        .clone()
+        .oneshot(common::get_with_cookie("/api/v1/me/read-progress", &cookie))
+        .await
+        .unwrap();
+    let body = common::body_json(resp).await;
+    assert_eq!(body["items"][0]["new_chapters_count"], 0);
+}
+
 #[sqlx::test(migrations = "./migrations")]
 async fn get_single_manga_returns_404_when_unread(pool: PgPool) {
     let h = common::harness(pool);

frontend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "mangalord-frontend",
-  "version": "0.94.1",
+  "version": "0.95.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "mangalord-frontend",
-      "version": "0.94.1",
+      "version": "0.95.0",
       "devDependencies": {
         "@lucide/svelte": "^1.16.0",
         "@playwright/test": "^1.48.0",

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mangalord-frontend",
-  "version": "0.94.1",
+  "version": "0.95.0",
   "private": true,
   "type": "module",
   "scripts": {