feat(dross): voice Phase 2b — clip retention (2.13.0)

'Keep voice clips' setting (default off). When on, /api/voice/transcribe
saves the audio (0600) to the owner-only ZFS subvol at /var/lib/void/
voice-clips (CT 311 mp0, replicated to Z3) + a voice_clips row (migration
029, transcript+metadata in void-db). New clips list/play/delete API +
Settings UI. Storage path is configurable (VOICE_CLIPS_DIR).

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

lib/db/repos/voice_clips.js

@@ -0,0 +1,26 @@
+import { pool } from '../pool.js';
+
+export async function create({ transcript = '', duration_ms = null, bytes = null, mime = null, path }) {
+  const { rows } = await pool.query(
+    `INSERT INTO voice_clips (transcript, duration_ms, bytes, mime, path)
+     VALUES ($1,$2,$3,$4,$5) RETURNING *`,
+    [transcript, duration_ms, bytes, mime, path]);
+  return rows[0];
+}
+
+export async function list(limit = 100) {
+  const { rows } = await pool.query(
+    `SELECT id, transcript, duration_ms, bytes, mime, created_at
+       FROM voice_clips ORDER BY created_at DESC LIMIT $1`, [limit]);
+  return rows;
+}
+
+export async function get(id) {
+  const { rows } = await pool.query(`SELECT * FROM voice_clips WHERE id = $1`, [id]);
+  return rows[0] || null;
+}
+
+export async function remove(id) {
+  const { rows } = await pool.query(`DELETE FROM voice_clips WHERE id = $1 RETURNING path`, [id]);
+  return rows[0] || null;   // returns {path} so the caller can unlink the file
+}