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/api/routes/dross.js

@@ -10,7 +10,7 @@ import * as agents from '../../db/repos/agents.js';
 import { runAgentTurn } from '../../ai/agent/run_turn.js';
 import { personaFor } from '../../ai/personas/index.js';
 
-const DEFAULT_SETTINGS = { avatar: 'soft-eye', accent: '#a86adf', persona: '', voiceMode: 'review' };
+const DEFAULT_SETTINGS = { avatar: 'soft-eye', accent: '#a86adf', persona: '', voiceMode: 'review', keepClips: false };
 const COMPANION_SLUG = 'companion';
 
 export const router = Router();
@@ -23,7 +23,8 @@ const settingsBody = z.object({
   avatar: z.enum(['soft-eye', 'wisp', 'motes']),
   accent: z.string().regex(/^#[0-9a-fA-F]{6}$/),
   persona: z.string().max(8000),
-  voiceMode: z.enum(['review', 'handsfree', 'action'])
+  voiceMode: z.enum(['review', 'handsfree', 'action']),
+  keepClips: z.boolean().default(false)
 });
 router.put('/settings', requireOwner, validate({ body: settingsBody }),
   asyncWrap(async (req, res) => res.json(await settings.set('dross', req.body))));

lib/api/routes/voice.js

@@ -1,24 +1,73 @@
 import { Router } from 'express';
 import multer from 'multer';
+import { randomUUID } from 'node:crypto';
+import { createReadStream } from 'node:fs';
+import { writeFile, unlink } from 'node:fs/promises';
+import path from 'node:path';
 import { asyncWrap } from '../errors.js';
 import { requireOwner } from '../cap.js';
 import * as whisper from '../../voice/whisper.js';
+import * as settings from '../../db/repos/app_settings.js';
+import * as clips from '../../db/repos/voice_clips.js';
 export const router = Router();
 
+const CLIPS_DIR = process.env.VOICE_CLIPS_DIR || '/var/lib/void/voice-clips';
 // In-memory upload; clips are small voice notes. 25 MB ceiling.
 const upload = multer({ storage: multer.memoryStorage(), limits: { fileSize: 25 * 1024 * 1024 } });
 
+function extFor(mime = '') {
+  if (mime.includes('ogg')) return '.ogg';
+  if (mime.includes('mp4') || mime.includes('m4a')) return '.m4a';
+  if (mime.includes('wav')) return '.wav';
+  return '.webm';
+}
+
 // POST /api/voice/transcribe — owner-only. multipart field `audio`. Returns { text }.
-// (Phase 2b will optionally persist the clip + transcript when keepClips is on.)
+// When the Dross "keepClips" setting is on, the clip + transcript are retained.
 router.post('/transcribe', requireOwner, upload.single('audio'), asyncWrap(async (req, res) => {
   if (!req.file || !req.file.buffer?.length) {
     return res.status(400).json({ error: { code: 'no_audio', message: 'no audio supplied' } });
   }
+  let r;
   try {
-    const r = await whisper.transcribe(
+    r = await whisper.transcribe(
       req.file.buffer, req.file.originalname || 'clip.webm', req.file.mimetype || 'audio/webm');
-    res.json({ text: r.text, duration: r.duration ?? null });
   } catch {
-    res.status(503).json({ error: { code: 'stt_unavailable', message: 'transcription service unavailable' } });
+    return res.status(503).json({ error: { code: 'stt_unavailable', message: 'transcription service unavailable' } });
   }
+
+  const cfg = await settings.get('dross', {});
+  let clip_id = null;
+  if (cfg?.keepClips) {
+    try {
+      const id = randomUUID();
+      const mime = req.file.mimetype || 'audio/webm';
+      const filePath = path.join(CLIPS_DIR, id + extFor(mime));
+      await writeFile(filePath, req.file.buffer, { mode: 0o600 });
+      const row = await clips.create({
+        transcript: r.text, duration_ms: r.duration != null ? Math.round(r.duration * 1000) : null,
+        bytes: req.file.buffer.length, mime, path: filePath
+      });
+      clip_id = row.id;
+    } catch { /* retention is best-effort; never fail the transcript */ }
+  }
+  res.json({ text: r.text, duration: r.duration ?? null, clip_id });
+}));
+
+// GET /api/voice/clips — list retained clips (owner).
+router.get('/clips', requireOwner, asyncWrap(async (_req, res) => res.json(await clips.list())));
+
+// GET /api/voice/clips/:id/audio — stream the audio file (owner).
+router.get('/clips/:id/audio', requireOwner, asyncWrap(async (req, res) => {
+  const c = await clips.get(req.params.id);
+  if (!c) return res.status(404).json({ error: { code: 'not_found', message: 'clip not found' } });
+  res.setHeader('Content-Type', c.mime || 'audio/webm');
+  createReadStream(c.path).on('error', () => res.status(404).end()).pipe(res);
+}));
+
+// DELETE /api/voice/clips/:id — remove the row + the file (owner).
+router.delete('/clips/:id', requireOwner, asyncWrap(async (req, res) => {
+  const removed = await clips.remove(req.params.id);
+  if (removed?.path) { try { await unlink(removed.path); } catch { /* file may be gone */ } }
+  res.status(204).end();
 }));