Dashboard detail, library filtering/pagination, simplified playlist times,

job descriptions

Dashboard: format breakdown (FLAC/MP3/etc. counts), approximate library
size (bitrate*length/8, same approximation `beet stats` itself uses --
verified to match its "100.5 GiB" output exactly against the real
library), and a credential auth-state summary per scope (configured y/n
plus, for Bandcamp, cookie expiry parsed locally from the stored cookie
jar -- deliberately not a live network probe like pipeline-status.sh's
Qobuz check, since this renders on every dashboard load).

Library: was one unfiltered page dumping all 4072 tracks. Added search
(artist/title/album), playlist and format filter dropdowns, and real
SQL-level pagination (LIMIT/OFFSET, not fetch-everything-then-slice).
beets_service gained count_items()/distinct_formats() to support this.

Playlists: cron_expr is still the stored/scheduled representation, but the
UI now shows and edits a plain daily time picker instead of raw cron
syntax -- every playlist schedule today is a simple daily HH:MM anyway.
playlist_service.cron_to_time()/time_to_cron() convert at the router
boundary; verified round-trip against all real playlist cron values.

Jobs: each maintenance job now shows a short one-line description of what
it actually does (MAINTENANCE_JOB_DESCRIPTIONS), and "next run" is
formatted consistently with playlists' time style (HH:MM, with a day
qualifier for non-today runs -- maintenance jobs can be weekly/monthly,
unlike playlists' plain daily schedule).

Verified end-to-end against the real production data (4072 tracks, 100.5
GiB, real credentials): stats/format-breakdown/search/pagination all
correct, all 7 credential scopes report configured with Bandcamp's real
cookie expiry (325 days), and a full authenticated page-render sweep
(dashboard, library with every filter combination, playlist detail,
jobs) all returned 200 with no template errors.

app/routers/library.py

@@ -10,11 +10,39 @@ router = APIRouter(prefix="/library", tags=["library"])
 templates = Jinja2Templates(directory="app/templates")
 
 
+PAGE_SIZE = 50
+
+
 @router.get("")
-async def library_index(request: Request, grouping: str | None = None, user: dict = Depends(require_auth)):
-    items = beets_service.query_items(grouping=grouping)
+async def library_index(
+    request: Request,
+    grouping: str | None = None,
+    format: str | None = None,
+    q: str | None = None,
+    page: int = 1,
+    user: dict = Depends(require_auth),
+):
+    page = max(1, page)
+    offset = (page - 1) * PAGE_SIZE
+    items = beets_service.query_items(grouping=grouping, search=q, format=format, limit=PAGE_SIZE, offset=offset)
+    total = beets_service.count_items(grouping=grouping, search=q, format=format)
+    total_pages = max(1, (total + PAGE_SIZE - 1) // PAGE_SIZE)
+    stats = beets_service.stats()
+
     return templates.TemplateResponse(
-        request, "library/index.html", {"items": items, "grouping": grouping}
+        request,
+        "library/index.html",
+        {
+            "items": items,
+            "grouping": grouping or "",
+            "format": format or "",
+            "q": q or "",
+            "page": page,
+            "total_pages": total_pages,
+            "total": total,
+            "all_formats": beets_service.distinct_formats(),
+            "all_groupings": stats["groupings"],
+        },
     )