Add admin analytics, metadata collection, and grouped lyric cues

Queue reviewable Whisper drafts from the song list and lyrics editor. Preserve line breaks within one timed cue across editing, saving, reporting, and service views.

Add storage and listening analytics with a durable metadata collector, related-search depth, video limits, thumbnail storage, and a browsable metadata library.

server/db.js

@@ -157,6 +157,28 @@ export async function initDb() {
     );
     CREATE INDEX IF NOT EXISTS idx_video_channel ON video_channels (channel,updated_at DESC,video_id);
 
+    CREATE TABLE IF NOT EXISTS video_details (
+      video_id TEXT PRIMARY KEY, metadata TEXT NOT NULL, updated_at INTEGER NOT NULL
+    );
+    CREATE TABLE IF NOT EXISTS metadata_collections (
+      id TEXT PRIMARY KEY, query TEXT NOT NULL, max_videos INTEGER NOT NULL, depth INTEGER NOT NULL,
+      status TEXT NOT NULL DEFAULT 'queued', state TEXT NOT NULL DEFAULT '{}', error TEXT,
+      lease_until INTEGER NOT NULL DEFAULT 0, owner TEXT,
+      created_at INTEGER NOT NULL, updated_at INTEGER NOT NULL
+    );
+    CREATE INDEX IF NOT EXISTS idx_collections_queue ON metadata_collections (status,created_at);
+
+    CREATE TABLE IF NOT EXISTS lyric_transcriptions (
+      id TEXT PRIMARY KEY, video_id TEXT NOT NULL, status TEXT NOT NULL DEFAULT 'queued',
+      base_rev INTEGER NOT NULL DEFAULT 0, result TEXT, error TEXT, stage TEXT NOT NULL DEFAULT 'queued',
+      attempts INTEGER NOT NULL DEFAULT 0, lease_token TEXT, lease_until INTEGER NOT NULL DEFAULT 0,
+      created_at INTEGER NOT NULL, updated_at INTEGER NOT NULL
+    );
+    CREATE UNIQUE INDEX IF NOT EXISTS idx_transcription_active ON lyric_transcriptions (video_id)
+      WHERE status IN ('queued','running');
+    CREATE INDEX IF NOT EXISTS idx_transcription_queue ON lyric_transcriptions (status,created_at);
+    CREATE TABLE IF NOT EXISTS lyrics_worker_state (id INTEGER PRIMARY KEY CHECK(id=1), last_seen INTEGER NOT NULL);
+
     -- Shared per-video documents (kind = lyrics | chapters), visible to every
     -- user. The live copy is here; every save also lands in video_note_revs
     -- as a full snapshot, which is the server-side backup and undo history.