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.

frontend/lyrics-core.js

@@ -11,6 +11,7 @@
  *   @ Key G, Capo 2 (Play F), 70 BPM                    tags
  *   [00:12.00][01:30.00] repeated line                  LRC multi-stamp
  *   [offset:+500]                                       LRC offset (ms, + = sooner)
+ *   | You can do anything                              continuation, same cue
  * Other LRC headers ([ar:], [ti:], …) are ignored.
  *
  * Sync offset: a line is shown at (t + offset) seconds of playback, so a
@@ -60,9 +61,15 @@
     const lines = [];
     const tags = [];
     let offset = null;
+    let group = [];
     for (const rawLine of String(text || '').replace(/\r/g, '').split('\n')) {
       let rest = rawLine.trim();
       if (!rest) continue;
+      if (rest.startsWith('| ') && group.length) {
+        for (const line of group) line.text += '\n' + rest.slice(2).trim();
+        continue;
+      }
+      group = [];
       const header = rest.match(HEADER_RE);
       if (header && !/^\d/.test(header[1])) {
         if (header[1].toLowerCase() === 'offset') {
@@ -83,8 +90,9 @@
       if (rest.startsWith('#')) { kind = 'section'; rest = rest.replace(/^#+/, '').trim(); }
       else if (rest.startsWith('!')) { kind = 'cue'; rest = rest.slice(1).trim(); }
       if (!rest) continue;
-      if (!stamps.length) lines.push({ t: null, text: rest, kind });
-      for (const t of stamps) lines.push({ t: Math.round(t * 100) / 100, text: rest, kind });
+      group = stamps.length ? stamps.map(t => ({ t: Math.round(t * 100) / 100, text: rest, kind }))
+        : [{ t: null, text: rest, kind }];
+      lines.push(...group);
     }
     // A fully timed sheet (typical .lrc with repeated-chorus stamps) is put in
     // time order; a partly timed one keeps the order it was written in.
@@ -100,7 +108,8 @@
     for (const l of (doc && doc.lines) || []) {
       const stamp = l.t === null || l.t === undefined ? '' : `[${fmtStamp(l.t)}] `;
       const mark = l.kind === 'section' ? '# ' : l.kind === 'cue' ? '! ' : '';
-      out.push(stamp + mark + l.text);
+      const parts = String(l.text || '').split('\n');
+      out.push(stamp + mark + parts[0], ...parts.slice(1).map(part => '| ' + part));
     }
     return out.join('\n');
   }