feat(admin): all-podcasts view — disk-first maintenance for every feed

§0 item 8 (Phase-4 item 1 pulled forward, user directive: maintenance
tooling ships WITH the features it maintains):

- /admin/podcasts (AdminMiddleware): every feed from EVERY user via the
  RLS admin escape (first-admin identity, poller/fetcher contract) —
  feed + host, library, subscriber count/names, downloaded/total, DISK
  USAGE, last fetch. Sorted disk DESC ('what's eating the disk'),
  totals header (feeds · episodes · bytes on disk).
- Per-feed actions: Refresh · Delete files (rows → pending, disk freed;
  confirms spell out the re-materialization contract) · Remove feed
  (rows + files for everyone — the same admin delete as the detail
  page). All confirms ride the global confirm modal.
- New sqlc: ListAllPodcastFeedsAdmin (correlated aggregates),
  ResetPodcastEpisodeFileDeleted / ResetPodcastFeedFilesDeleted —
  downloaded rows reset to pending with download-derived facts cleared
  (audio_metadata, chapter_count, cover, size, mime); file_path KEPT
  (fetch-maintained layout — a re-download lands on the same path).
  file deletion via the existing DeleteFeedFiles file-removal pattern
  (episode files + .cover.jpg siblings).
- Poll upsert never touches download_state, so deleted files STAY
  deleted — a feed refresh re-lists metadata but re-materializes
  nothing (pinned by TestAdminDeleteEpisodeFiles).
- Per-episode admin delete-file: POST /feeds/:id/episodes/:eid/
  delete-file (admin) — one episode's file gone, row pending, siblings
  untouched; HX swaps the episode list. (Found while testing: the
  handler first read c.Param("id") — the FEED's uuid — instead of
  :eid; the 404 'episode not found' trail led straight to it.)
- Tests: admin sees other users' feeds + subscriber names; regular
  users 403 on page AND actions; single + feed-level deletion reset
  rows/clear facts/delete files; refresh leaves pending rows pending.
- Admin nav gains 'Podcasts' under Administration.

Wrong-gotcha note for future agents: parseUUID on c.Param('id') inside
a /feeds/:id/episodes/:eid route resolves the FEED, not the episode.

internal/database/querier.go

@@ -602,6 +602,12 @@ type Querier interface {
 	// Link unlinked book to media item
 	LinkUnlinkedBook(ctx context.Context, arg LinkUnlinkedBookParams) (UnlinkedBooks, error)
 	ListAllConflictsByUserAndStatus(ctx context.Context, arg ListAllConflictsByUserAndStatusParams) ([]ListAllConflictsByUserAndStatusRow, error)
+	// Admin all-podcasts view (§0 item 8 / Phase-4 item 1): EVERY feed from
+	// EVERY user with its maintenance aggregates. Runs under the first-
+	// admin identity (invariant 12 — same contract as the poller). Sorted
+	// by disk usage DESC: the maintenance question is "what's eating the
+	// disk", so the hogs surface first.
+	ListAllPodcastFeedsAdmin(ctx context.Context) ([]ListAllPodcastFeedsAdminRow, error)
 	ListAllSyncQueueItems(ctx context.Context, arg ListAllSyncQueueItemsParams) ([]ListAllSyncQueueItemsRow, error)
 	ListConflictsByUser(ctx context.Context, userID pgtype.UUID) ([]ListConflictsByUserRow, error)
 	// ============================================
@@ -721,6 +727,17 @@ type Querier interface {
 	ReorderCollectionItems(ctx context.Context, arg ReorderCollectionItemsParams) error
 	// Re-parent all child rows of p_source onto p_target (defined in schema.sql)
 	ReparentMediaItemChildren(ctx context.Context, arg ReparentMediaItemChildrenParams) error
+	// Admin file deletion (§0 item 8): ONE downloaded episode's disk file
+	// was removed — reset the row to pending and clear the download-derived
+	// facts. file_path is deliberately KEPT: it is the fetch-maintained
+	// layout (written at fetch time, not download time), so a re-download
+	// lands on the same path. The poll upsert never touches download_state,
+	// so a deleted file stays deleted (invariant 2: polling never deletes;
+	// admins delete knowingly).
+	ResetPodcastEpisodeFileDeleted(ctx context.Context, id pgtype.UUID) error
+	// Same reset for EVERY downloaded episode of a feed (per-feed
+	// "Delete files" action on the admin view).
+	ResetPodcastFeedFilesDeleted(ctx context.Context, sourceFeedID pgtype.UUID) (int64, error)
 	ResetSystemCollectionMetadata(ctx context.Context, arg ResetSystemCollectionMetadataParams) error
 	ResolveHashConflict(ctx context.Context, arg ResolveHashConflictParams) error
 	// Ledger self-heal (faceted plan Phase 11): a scan that processes the