feat(facets): all-facets panel with under-filter counts (faceted plan Phase 7)

The 9 Batch A facets could not be SET from the web UI, the facets
endpoint had no in-app consumer, and the registry's libraryTypes hints
rendered nowhere. This phase closes all three.

- ONE UNION-ALL sqlc query (FacetCountsUnderFilters) computes all 14
  listable facets in a single round trip: each arm omits its OWN
  facet's filter block and carries every other registered facet's
  block (copied mechanically from SearchMediaItemsUnified) — classic
  faceted semantics: with filters active each facet counts under the
  others; with none, blocks are neutral and the counts are the v1
  global-per-library ones. One query serves both cases. The 14
  per-column Batch C queries are deleted.
- Endpoint: no facet param → the new all-facets shape
  ({facets: {param: [{value, display?, count}]}}), filters bound via
  the shared ParseMediaSearchParams, library_id optional (the
  All-Libraries view, family lens still enforced); facet=X keeps the
  pinned single-facet shape (now routed through the same query with
  neutral filters).
- SSR partial GET /media-items/facet-panel: templ renders the drawer's
  value lists — registry order, Batch D library-type scoping
  (FacetsForLibraryType: manga_type on manga, reading_direction on
  manga+comics, narrator on audiobooks; All view = union), prettified
  genre labels + language display names, active values marked. Family
  lens: out-of-set explicit library_id is 403.
- Drawer wiring: the panel fetches on drawer open and after every
  apply with the CURRENT filter query string; a value click toggles
  that facet's comma-joined filter (hidden input where the drawer has
  no field — same as deep links) and re-applies the form; chips and
  URL stay in sync. Values are server-rendered (rendering doctrine);
  bookshelf.ts owns only the click/fetch orchestration.
- prettifyGenre moves to internal/utils as the canonical
  implementation (services' display enrichment shares it; templ wraps
  it; the TS port in bookshelf.ts is unchanged).
- Drift guard extended: FacetCountsUnderFiltersParams must carry every
  registry facet's param, the bools as pgtype.Bool.

Tests: under-filter exactness (own-block omission, OR-within,
AND-across), family lens (hidden values absent; 403 on both shapes),
all-shape + pinned-shape coexistence, partial rendering with Batch D
scoping + active marking + 403. Full container suite green except the
documented pre-existing TestAdminCreateUser red.

web/static/input.css

@@ -874,6 +874,41 @@
     color: var(--text-secondary);
   }
 
+  /* ---------- Facet panel (filter drawer, Phase 7) ---------- */
+  /* The values are templ-rendered (templates/facet_panel.templ); this
+     is look only. A value button is plain until active: active means
+     "currently in that facet's filter" — accent-tinted like a chip. */
+  .facet-section-summary {
+    list-style: none;
+  }
+  .facet-section-summary::-webkit-details-marker {
+    display: none;
+  }
+  .facet-section-summary::before {
+    content: "▸";
+    display: inline-block;
+    margin-right: 0.5rem;
+    color: var(--text-secondary);
+    transition: transform 0.15s ease;
+    font-size: 0.7rem;
+  }
+  .facet-section[open] .facet-section-summary::before {
+    transform: rotate(90deg);
+  }
+  .facet-value-btn {
+    background-color: transparent;
+  }
+  .facet-value-btn:hover {
+    background-color: var(--surface-hover);
+  }
+  .facet-value-btn.facet-value-active {
+    background-color: var(--accent-muted);
+    color: var(--accent);
+  }
+  .facet-value-btn.facet-value-active span {
+    color: var(--accent);
+  }
+
   .loading-spinner {
     display: inline-block;
     width: 40px;