Turn Discord mic processing off for TTS playback

CURRENT.md

@@ -40,6 +40,13 @@ mobile draft at 390px.
   - [x] C11 preview caching: Discord-hosted image/GIF previews (WebP 320px, hash-addressed, 5 MiB
     cap, one attempt) run after every walk in both modes. Live run `...-20260916090722`:
     `previewed: 2`; thumbs served over `/api/media/<scrape>/<item>/thumb` (200).
+  - [x] C71 Voice processing gates off. The TTS line was ramping in because Discord's automatic
+    gain control (and echo/noise cancellation) were on. New `voice.processing` core action reads and
+    sets the gates (defaults off) plus an optional input volume; MCP `set_voice_processing` exposes
+    it, and `voice.join` disables all supported gates before connecting. Live check on the real
+    client: before = echoCancellation true, automaticGainControl true, noiseCancellation true,
+    noiseSuppression false; after = all false. Note these settings are client-local, not account
+    settings.
   - [x] C70 Speak panel honesty. Two bugs behind "speak stays queued": the panel never updated
     `#tts-status` after queuing (now it polls the daemon and shows `speaking…`, `queued (N)`,
     `done`, then `idle`), and `/api/audio/speak` turned the panel's `null` option fields into 0 via