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/src/crawler/daemon.rs

@@ -46,7 +46,7 @@ use tokio::task::JoinSet;
 use tokio_util::sync::CancellationToken;
 
 use crate::crawler::content::SyncOutcome;
-use crate::crawler::jobs::{self, JobPayload, Lease, KIND_SYNC_CHAPTER_CONTENT};
+use crate::crawler::jobs::{self, JobPayload, Lease, KIND_SYNC_CHAPTER_CONTENT, KIND_SYNC_MANGA};
 use crate::crawler::pipeline;
 use crate::crawler::status::{Phase, StatusHandle};
 
@@ -76,6 +76,15 @@ pub trait ChapterDispatcher: Send + Sync {
     async fn dispatch(&self, payload: JobPayload) -> anyhow::Result<SyncOutcome>;
 }
 
+/// A full list-only walk that enqueues mangas missing from the DB as
+/// `SyncManga` jobs. Triggered on demand from the admin `/reconcile`
+/// endpoint (not on the cron). Mirrors [`MetadataPass`] so the endpoint can
+/// hold a `dyn` and tests can stub it.
+#[async_trait]
+pub trait ReconcilePass: Send + Sync {
+    async fn run(&self) -> anyhow::Result<crate::crawler::reconcile::ReconcileStats>;
+}
+
 /// Configuration for [`spawn`]. Use `None` for `metadata_pass` to disable
 /// the cron entirely (worker-pool-only mode — useful when only the
 /// bookmark-triggered enqueue path is wanted).
@@ -342,9 +351,9 @@ impl WorkerContext {
                     _ = self.cancel.cancelled() => return,
                 }
             }
-            let leases = match jobs::lease(
+            let leases = match jobs::lease_kinds(
                 &self.pool,
-                Some(KIND_SYNC_CHAPTER_CONTENT),
+                &[KIND_SYNC_CHAPTER_CONTENT, KIND_SYNC_MANGA],
                 1,
                 LEASE_DURATION,
             )