feat(crawler): reconcile pass to enqueue mangas missing from the DB (0.85.0)

The interleaved metadata pass misses mangas to list drift (a title slips a
pagination slot during the slow detail walk). Add a reconcile pass: a cheap,
full, list-only walk (refs only, no detail visit, no early stop) that
set-diffs the walked keys against manga_sources and enqueues the strictly-
missing ones as SyncManga jobs. A set-diff is immune to drift — a manga only
has to appear somewhere in the list.

- Build the previously-dead SyncManga worker by extending RealChapterDispatcher
  to run the shared pipeline::process_manga_ref (fetch → upsert → cover →
  chapters), refactored out of run_metadata_pass so both paths stay in lockstep.
  The crawl worker now leases both sync_chapter_content and sync_manga
  (jobs::lease_kinds); both serialize on the single exclusive browser.
- SyncManga payload carries url + title so the worker can rebuild the ref and
  the dead-jobs/history UI can label a missing manga that has no manga row yet.
- "Missing" = strict NOT EXISTS (dropped rows count as present). Re-enqueue is
  skipped when a pending/running/dead SyncManga job already exists, so a gone
  manga (detail 404 → retries → dead) is left dead and not retried.
- New POST /v1/admin/crawler/reconcile (fire-and-forget, shares
  manual_pass_lock) + "Reconcile missing" admin button + Reconciling status
  phase streamed over SSE.
- dead-jobs/history queries surface payload title/url/key; tables fall back to
  them for sync_manga rows; both searches match the payload title.

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

backend/tests/api_admin_crawler.rs

@@ -206,6 +206,7 @@ async fn control_endpoints_return_503_when_daemon_disabled(pool: PgPool) {
     let cookie = seed_admin(&pool, &h.app).await;
     for uri in [
         "/api/v1/admin/crawler/run",
+        "/api/v1/admin/crawler/reconcile",
         "/api/v1/admin/crawler/browser/restart",
         "/api/v1/admin/crawler/session/clear-expired",
     ] {
@@ -779,6 +780,45 @@ async fn job_history_lists_filters_and_paginates(pool: PgPool) {
     assert_eq!(resp.status(), StatusCode::FORBIDDEN);
 }
 
+#[sqlx::test(migrations = "./migrations")]
+async fn job_history_surfaces_sync_manga_payload_title(pool: PgPool) {
+    // A reconcile-enqueued sync_manga job that died has no manga row, so the
+    // history row must fall back to the payload title/url and be searchable.
+    sqlx::query("INSERT INTO crawler_jobs (id, payload, state, last_error) VALUES ($1, $2, 'dead', 'broken-page body signature')")
+        .bind(Uuid::new_v4())
+        .bind(json!({
+            "kind": "sync_manga",
+            "source_id": "target",
+            "source_manga_key": "gone-1",
+            "url": "http://x/manga/gone-1",
+            "title": "Ghost Manga",
+        }))
+        .execute(&pool)
+        .await
+        .unwrap();
+    let h = harness(pool.clone());
+    let cookie = seed_admin(&pool, &h.app).await;
+
+    let resp = h
+        .app
+        .clone()
+        .oneshot(get_with_cookie(
+            "/api/v1/admin/crawler/history?search=ghost",
+            &cookie,
+        ))
+        .await
+        .unwrap();
+    assert_eq!(resp.status(), StatusCode::OK);
+    let body = body_json(resp).await;
+    assert_eq!(body["page"]["total"], 1);
+    let row = &body["items"][0];
+    assert_eq!(row["kind"], "sync_manga");
+    assert_eq!(row["manga_title"], serde_json::Value::Null);
+    assert_eq!(row["payload_title"], "Ghost Manga");
+    assert_eq!(row["source_url"], "http://x/manga/gone-1");
+    assert_eq!(row["source_key"], "gone-1");
+}
+
 // ---------------------------------------------------------------------------
 // Operation metrics: durations, averages, recent-ops log.
 // ---------------------------------------------------------------------------