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.

web/src/header.ts

@@ -1,5 +1,4 @@
 import { Alpine } from "./alpine";
-import { initializeSearch } from "./search";
 import {
   initializeTheme,
   changeTheme,
@@ -137,7 +136,6 @@ Alpine.data("header", () => ({
     } catch {
       this.openPanel = window.location.pathname.startsWith("/admin") ? "admin" : null;
     }
-    initializeSearch();
     this.initializeTheme();
     this.loadWoodPaneling();
     this.updateWoodPanelingIndicators();
@@ -176,7 +174,6 @@ Alpine.data("header", () => ({
     this.openPanel = null;
   },
   logout,
-  initializeSearch,
   initializeTheme,
   changeTheme,
   changeWoodPaneling,