fix(voice): silent cycles never end the chat while the agent is busy or TTS is playing

The continuous-voice no-speech counter (3 strikes -> voice off) counted
every silent capture cycle unconditionally. During a long agent turn
(thinking/tool-calling for minutes) or while TTS is speaking, the user
is CORRECTLY silent — those cycles ended the voice chat under them.

- hermes_cli/voice.py: new set_voice_busy_probe() seam + _voice_activity_held()
  (TTS-playing via the existing _tts_playing Event, agent-busy via the
  registered probe). Both the continuous-loop strike path and the
  force-transcribe single-shot strike path skip counting while held.
  Fail-open: a broken probe counts cycles as before.
- tui_gateway/server.py: registers _any_session_running() as the probe
  on voice.record start (voice is process-global; any running session holds).
- cli.py: classic CLI strike path skips counting while _agent_running
  or TTS playback is in flight.

Stop phrase and barge-in still work during the hold (own paths).
Includes a fixture fix for the #71083 cherry-pick: the fake tools.tts_tool
module needs _load_tts_config (main's tts_streaming imports it).

cli.py

@@ -12000,14 +12000,26 @@ class HermesCLI(CLIAgentSetupMixin, CLICommandsMixin, CLIBillingMixin):
                 pass
 
             # Track consecutive no-speech cycles to avoid infinite restart loops.
+            # While the agent is mid-turn or TTS is speaking, the user is
+            # CORRECTLY silent (waiting/listening) — those cycles must not
+            # count, or a multi-minute tool run ends the voice chat under
+            # the user. The stop phrase and barge-in still work during the
+            # hold (they run on their own paths above).
             stop_continuous_restart = False
+            _activity_hold = bool(
+                getattr(self, "_agent_running", False)
+                or not self._voice_tts_done.is_set()
+            )
             if not submitted:
-                self._no_speech_count = getattr(self, '_no_speech_count', 0) + 1
-                if self._no_speech_count >= 3:
-                    self._voice_continuous = False
-                    self._no_speech_count = 0
-                    _cprint(f"{_DIM}No speech detected 3 times, continuous mode stopped.{_RST}")
-                    stop_continuous_restart = True
+                if _activity_hold:
+                    pass  # held: keep listening without counting the cycle
+                else:
+                    self._no_speech_count = getattr(self, '_no_speech_count', 0) + 1
+                    if self._no_speech_count >= 3:
+                        self._voice_continuous = False
+                        self._no_speech_count = 0
+                        _cprint(f"{_DIM}No speech detected 3 times, continuous mode stopped.{_RST}")
+                        stop_continuous_restart = True
             else:
                 self._no_speech_count = 0