fix: address reader-UI feedback (shorts, search, tags, login, UX)

- Shorts: confirm via youtube.com/shorts/<id> probe (SOCS cookie bypasses the
  consent redirect) instead of a 60s heuristic; concurrent probing, shorts_probed
  flag, scheduled refinement (migration 0005)
- Search: match title + channel name only (descriptions caused noisy results)
- Faceted tag filtering: AND across categories (language AND topic narrows),
  OR within a category; any/all toggle applies to topics
- Language detection: majority vote over individual titles (fixes misdetections
  like multipoleguy -> English; drops bogus Polish/Romanian)
- Login: drop forced consent so returning sign-in is quick (select_account)
- Feed cards: clickable channel name (opens channel), persistent saved badge,
  undo toast on hide, Hidden view to restore; tag chips show counts in tooltip

backend/app/scheduler.py

@@ -12,6 +12,7 @@ from app.sync.runner import (
     run_enrich,
     run_recent_backfill,
     run_rss_poll,
+    run_shorts,
 )
 
 logger = logging.getLogger("subfeed.scheduler")
@@ -53,6 +54,10 @@ def _autotag_job() -> None:
     _job("autotag", lambda db: run_autotag_all(db, only_missing=True))
 
 
+def _shorts_job() -> None:
+    _job("shorts", run_shorts)
+
+
 def start_scheduler() -> None:
     global _scheduler
     if not settings.scheduler_enabled or _scheduler is not None:
@@ -76,6 +81,12 @@ def start_scheduler() -> None:
         minutes=settings.autotag_interval_minutes,
         id="autotag",
     )
+    scheduler.add_job(
+        _shorts_job,
+        "interval",
+        minutes=settings.shorts_probe_interval_minutes,
+        id="shorts",
+    )
     scheduler.start()
     _scheduler = scheduler
     logger.info("scheduler started")