fix(sync): queue a watch position the server could not be told about (DR-154)

sync_queue and its drain (DR-131) were built, tested and running, but the
stop-report path never fed them, so closing a video while the server was
unreachable lost the resume point outright.

HybridRepository::report_playback_stopped is a bare pass-through to the
online repository ("Playback reporting goes directly to server"), and on
failure the error surfaced to a frontend catch whose own comment read
"Server error - could queue, but for now just log". Both producers that
would have queued it -- PlaybackReporter::queue_for_sync in Rust and
syncService.queuePlaybackProgress on the frontend -- have no callers on
the playback path. user_data.pending_sync was dutifully set to 1, but
nothing drains that flag for positions the way favourites do (DR-120).

The command layer now enqueues a report_playback_stopped row whenever the
push fails; the existing drain already parses and replays that operation.

The pending row for an item is superseded in place rather than appended
to: progress is reported every 10s, so a server that stays down would
otherwise add a row per tick, all obsoleted by the newest -- the
unbounded queue DR-131 exists to prevent. Only pending/failed rows are
superseded, since reviving an abandoned row restores that same growing
counter. Queueing is best-effort and never fails the command: the local
position is already saved, so a failed queue write must not be reported
as a lost position.

Verified red->green in the jellytau-builder image: the four new tests
failed to compile (enqueue_playback_stopped not found) before the fix.
Full Rust suite passes (627 tests), cargo fmt clean, clippy adds no new
warnings; frontend suite (933) and svelte-check also clean.

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

src/lib/services/playbackReporting.ts

@@ -103,15 +103,15 @@ export async function reportPlaybackStopped(itemId: string, positionSeconds: num
     }
   }
 
-  // Queue for sync to server (the sync service will handle retry logic)
+  // Report to the server. Rust queues the position for the next reconnect if
+  // the server cannot be reached (DR-154), so a throw here means the report
+  // did not land *this time* — not that the position was lost.
   if (userId && positionSeconds > 0) {
     try {
-      // Get the repository to check if we should queue
       const repo = auth.getRepository();
       await repo.reportPlaybackStopped(itemId, positionMs);
     } catch (e) {
-      console.error("[PlaybackReporting] Failed to report to server:", e);
-      // Server error - could queue, but for now just log
+      console.warn("[PlaybackReporting] Stop-report did not reach the server; queued for sync:", e);
     }
   }
 }