TTS: gate auto audio on inbound voice notes (#1667)

Co-authored-by: Sebastian <sebslight@gmail.com>

docs/gateway/configuration.md

@@ -1509,7 +1509,7 @@ voice notes; other channels send MP3 audio.
 {
   messages: {
     tts: {
-      enabled: true,
+      auto: "always", // off | always | inbound | tagged
       mode: "final", // final | all (include tool/block replies)
       provider: "elevenlabs",
       summaryModel: "openai/gpt-4.1-mini",
@@ -1546,8 +1546,10 @@ voice notes; other channels send MP3 audio.
 ```
 
 Notes:
-- `messages.tts.enabled` can be overridden by local user prefs (see `/tts on`, `/tts off`).
-- `prefsPath` stores local overrides (enabled/provider/limit/summarize).
+- `messages.tts.auto` controls auto‑TTS (`off`, `always`, `inbound`, `tagged`).
+- `/tts off|always|inbound|tagged` sets the per‑session auto mode (overrides config).
+- `messages.tts.enabled` is legacy; doctor migrates it to `messages.tts.auto`.
+- `prefsPath` stores local overrides (provider/limit/summarize).
 - `maxTextLength` is a hard cap for TTS input; summaries are truncated to fit.
 - `summaryModel` overrides `agents.defaults.model.primary` for auto-summary.
   - Accepts `provider/model` or an alias from `agents.defaults.models`.