fix(voice): honor wake_word.start_new_session on every surface

start_new_session was respected only by the CLI; the TUI and desktop GUI
always opened a fresh session on wake, ignoring the config. The gateway
now carries the flag in the wake.detected payload and both clients honor
it (open a fresh session vs. continue the current one), matching the CLI.

apps/desktop/src/app/desktop-controller.tsx

@@ -746,7 +746,10 @@ export function DesktopController() {
   const handleGatewayEventWithWake = useCallback(
     (event: Parameters<typeof handleDesktopGatewayEvent>[0]) => {
       if (event.type === 'wake.detected') {
-        startFreshSessionDraft()
+        const payload = event.payload as { start_new_session?: boolean } | undefined
+        if (payload?.start_new_session !== false) {
+          startFreshSessionDraft()
+        }
         requestVoiceConversationStart()
         return
       }

tui_gateway/server.py

@@ -17630,19 +17630,22 @@ def _wake_on_detect() -> None:
     with _wake_lock:
         sid = _wake_event_sid
         transport = _wake_transport
+    phrase, new_session = "", True
     try:
-        from tools.wake_word import wake_phrase
-        phrase = wake_phrase()
+        from tools.wake_word import load_wake_word_config, wake_phrase
+        cfg = load_wake_word_config()
+        phrase = wake_phrase(cfg)
+        new_session = bool(cfg.get("start_new_session", True))
     except Exception:
-        phrase = ""
+        pass
     logger.info("wake.detected: emitting to sid=%r (transport=%s)",
                 sid, type(transport).__name__ if transport else None)
     # Bind the arming request's transport so write_json reaches the right peer
     # (WS for desktop/dashboard) instead of falling back to stdio on this
-    # background thread.
+    # background thread. Carry start_new_session so every surface honors it.
     token = bind_transport(transport) if transport is not None else None
     try:
-        _emit("wake.detected", sid, {"phrase": phrase})
+        _emit("wake.detected", sid, {"phrase": phrase, "start_new_session": new_session})
     finally:
         if token is not None:
             reset_transport(token)

ui-tui/src/app/createGatewayEventHandler.ts

@@ -941,10 +941,12 @@ export function createGatewayEventHandler(ctx: GatewayEventHandlerContext): (ev:
       }
 
       case 'wake.detected': {
-        // "Hey Hermes": open a fresh session, then arm voice capture so the
-        // user can speak their request hands-free. Mirrors the CLI flow.
+        // "Hey Hermes": optionally open a fresh session (start_new_session),
+        // then arm voice capture so the user can speak hands-free. Mirrors CLI.
         void (async () => {
-          await newSession()
+          if (ev.payload?.start_new_session !== false) {
+            await newSession()
+          }
           const sid = getUiState().sid
           if (!sid) {
             return

ui-tui/src/gatewayTypes.ts

@@ -589,7 +589,7 @@ export type GatewayEvent =
     }
   | { payload?: { state?: 'idle' | 'listening' | 'transcribing' }; session_id?: string; type: 'voice.status' }
   | { payload?: { no_speech_limit?: boolean; text?: string }; session_id?: string; type: 'voice.transcript' }
-  | { payload?: { phrase?: string }; session_id?: string; type: 'wake.detected' }
+  | { payload?: { phrase?: string; start_new_session?: boolean }; session_id?: string; type: 'wake.detected' }
   | { payload?: { reason?: string }; session_id?: string; type: 'dashboard.new_session_requested' }
   | { payload: { line: string }; session_id?: string; type: 'gateway.stderr' }
   | {