feat(search): viewer progress + completed badges; dropdown to templ

Search results now show where you are in a book: a completed check at
the 0.999 threshold (same cut as the filter status arms), a partial
progress bar along the cover while mid-read, nothing when you never
opened it. Rendered in BookCard (any grid whose adapter loads viewer
progress) and in the header-search dropdown rows.

The progress rides a LEFT JOIN reading_progress on the SAME user_id
param SearchMediaItemsUnified already binds for library visibility —
one requester param, no new wire inputs, row-neutral join (the table
is UNIQUE per media_item+user). SearchMediaItemsUnifiedRow and BookInfo
gain the keys additively (viewer_percentage null when unknown,
library_name empty on feeds that don't load it); contract_pins.md
carries the changelog entry and the pin tests widen in lockstep.

The header dropdown itself migrates off the innerHTML string renderer
in search.ts (a rendering-ownership violation: a templ twin existed via
the HX-Request branch). The input now hx-gets layout=dropdown and swaps
the new templ SearchResults partial — titles/authors highlighted
server-side (escape-first, safe by construction), rows with the same
progress overlays — while a slim Alpine component owns only
client-local state (min-length gating, open/close, keyboard selection,
htmx lifecycle). web/src/rendering-allowlist.txt drops the search.ts
baseline to zero accordingly.

Integration test pins the per-user join (fresh user sees 1.0/0.42/null
on the fixture; the shared admin sees null everywhere — read-only) and
the dropdown partial's overlays/count/row count.

docs/contract_pins.md

@@ -37,14 +37,15 @@ These are the response SHAPES (JSON key sets, not values) frozen by the
 | `CollectionsJSON` | `GET /api/collections/:id` (all 4 branches) | envelope `id, user_id, name, description, color, icon, auto_assign_rules, view_settings, books[], book_count, is_smart, created_at`; books = `BookInfo` |
 | | `POST /api/collections/preview` | bare `{items: BookInfo[]}` |
 | `SeriesJSON` | `GET /api/series/books?name=&library_id=` | `{name, library_id, books: BookInfo[], total}` |
-| `SearchJSON` | `GET /api/media-items/search?q=&library_id=` | top-level array of `SearchMediaItemsUnifiedRow` (47 keys) |
+| `SearchJSON` | `GET /api/media-items/search?q=&library_id=` | top-level array of `SearchMediaItemsUnifiedRow` (47 keys + viewer_percentage) |
 | `DashboardSections` | `GET /api/dashboard/sections` | `{sections[]: {id, collection_id, is_system, title, description, icon, items: BookInfo[], view_all_url, priority}}` |
 | `MediaListBothBranches` | `GET /api/media-items` (unscoped) | `{data: [38-key resolved map]}` (intentionally divergent from the scoped branch until the row-shape collapse batch) |
 | | `GET /api/media-items?library_id=&sort=` | `{data: [raw ListMediaItemsSortedRow, 70 sqlc keys]}` |
 | `SSRPages` | `/bookshelf`, `/collections`, `/collections/:id`, `/series`, `/series/detail`, `/tags/detail` | 200 + stable title/substring markers |
 
 `BookInfo` (every card surface): `media_item_id, title, author,
-cover_image_path, has_conflict, format_group, badge`.
+cover_image_path, has_conflict, format_group, badge, viewer_percentage,
+library_name`.
 
 ## Changelog (additive keys per batch)
 
@@ -414,3 +415,20 @@ cover_image_path, has_conflict, format_group, badge`.
   BEFORE Rescan All — force rescan stamps books with the current
   setting, so bump-first + force = one pass of work; force-first +
   bump = the trickle re-derives everything again (wasted, not harmful).
+
+## 2026-10-27 — Search-progress batch: viewer progress on cards
+- **`SearchJSON`**: `SearchMediaItemsUnifiedRow` + `viewer_percentage`
+  (float 0..1, NULL when the requester never opened the book). The
+  query LEFT JOINs `reading_progress` on the SAME `user_id` param the
+  library-visibility join already binds — one requester param, no new
+  wire inputs; the join is row-neutral (UNIQUE(media_item, user)).
+- **`BookInfo`** (CollectionsJSON / SeriesJSON / preview /
+  DashboardSections / search cards): + `viewer_percentage` (JSON null
+  when nil) and + `library_name` (empty on feeds that don't load it —
+  only the search-unified adapter populates both today). Adapters
+  other than BookCardsFromUnified keep emitting null/""; templ cards
+  render the progress bar/completed check only when populated.
+- The header-search dropdown now renders the templ `SearchResults`
+  partial (layout=dropdown on the same endpoint, HX-Request) instead
+  of the retired innerHTML renderer in web/src/search.ts — same
+  endpoint, same auth, content server-rendered.