music: fresh-on-refresh reindex, resync logs, and stop the junk-cover rebuild loop

- POST /reindex now runs the build to completion before responding (via a
  coalescing reindexNow), and GET /manifest ensures a fresh (debounced 3s)
  index first — so on-disk changes show up on a plain app refresh, not only
  via the explicit reindex sheet.
- Log each resync in the officer-music sidecar (start + one-line summary,
  or a failure line).
- Fix albums whose cover file isn't a decodable image (junk .jpg): the
  manifest cover flag and the skip check now reflect whether a cover was
  actually cached, so they settle to cover:false instead of rebuilding every
  run (and the app no longer 404s fetching a cover that was never there).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/servers/sidecar/music/index.ts

@@ -4,7 +4,8 @@ import type { SidecarCommand, SidecarEvent } from '../protocol';
 import { createSidecarConnector } from '../connect';
 import { streamAudioFile } from './stream-audio';
 import {
-  buildMusicIndex,
+  reindexNow,
+  ensureIndexFresh,
   getIndexStatus,
   getManifest,
   albumVersion,
@@ -31,7 +32,8 @@ const DATA_PATH = process.env.DATA_PATH ?? join(process.cwd(), 'data');
 //
 //   GET  /stream?path=<home-relative>      audio with Range→206 (Content-Range/Length/Accept-Ranges)
 //                                          + `X-Audio-Duration` (seconds, ffprobe). 400/404/416.
-//   GET  /manifest                         { version, generatedAt, albums: { "<rel>": { v, cover, tracks, disco? } } }
+//   GET  /manifest                         ensures a fresh index (debounced rebuild) then returns
+//                                          { version, generatedAt, albums: { "<rel>": { v, cover, tracks, disco? } } }
 //   GET  /meta?path=<rel>                  album meta.json (IndexMeta). ETag: <v>; If-None-Match → 304.
 //   GET  /cover?path=<rel>                 compressed cover.jpg.       ETag: <v>; If-None-Match → 304.
 //   GET  /discography?path=<artist rel>    artist discography.json (only where manifest entry has
@@ -39,7 +41,7 @@ const DATA_PATH = process.env.DATA_PATH ?? join(process.cwd(), 'data');
 //                                          "<Type>" } }, Type ∈ Studio/Live/Compilation/Single/EP/…
 //                                          ETag: <v>; If-None-Match → 304. Source: each artist folder's
 //                                          _discography.md (normalized; the md itself is never modified).
-//   POST /reindex                          start an async build; returns IndexStatus (running: true).
+//   POST /reindex                          run the build to COMPLETION, then return the final IndexStatus.
 //   GET  /reindex/status                   IndexStatus snapshot.
 //   GET  /reindex/stream                   SSE. Triggers a build if idle (`?trigger=0` = watch-only).
 //                                          `event: progress` (IndexStatus) throttled ~200ms, then one
@@ -85,8 +87,11 @@ const server = Bun.serve({
     // ── Index build ──
     if (url.pathname === '/reindex') {
       if (req.method !== 'POST') return new Response('Method not allowed', { status: 405 });
-      void buildMusicIndex(); // fire-and-forget; sets running=true synchronously before the first await
-      return json(getIndexStatus());
+      // Run the resync to completion, THEN respond — so the caller's manifest read right after is fresh.
+      // Incremental builds are near-instant (unchanged albums skip by version stamp). reindexNow joins
+      // an in-flight build rather than starting a second.
+      const result = await reindexNow();
+      return json(result);
     }
     if (url.pathname === '/reindex/status') return json(getIndexStatus());
 
@@ -94,7 +99,7 @@ const server = Bun.serve({
     // streams `progress` events until the build finishes, ending with a `done` event carrying the report.
     if (url.pathname === '/reindex/stream') {
       const trigger = url.searchParams.get('trigger') !== '0';
-      if (trigger && !getIndexStatus().running) void buildMusicIndex();
+      if (trigger) void reindexNow();
 
       const encoder = new TextEncoder();
       const stream = new ReadableStream({
@@ -139,7 +144,12 @@ const server = Bun.serve({
     }
 
     // ── Sync surface ──
-    if (url.pathname === '/manifest') return json(await getManifest());
+    if (url.pathname === '/manifest') {
+      // Every app refresh funnels through here, so rebuild the index first (debounced) — this is what
+      // makes on-disk changes show up on a plain refresh, not only via the explicit reindex sheet.
+      await ensureIndexFresh();
+      return json(await getManifest());
+    }
 
     if (url.pathname === '/meta' || url.pathname === '/cover' || url.pathname === '/discography') {
       const rel = url.searchParams.get('path');