Add microphone picker and device management features

- Implement `list_input_devices` to retrieve and filter input-capable audio devices.
- Create `MicPickerDialog` for selecting and saving microphone settings.
- Add `set_env_value` function to update .env file with selected microphone index.
- Update UI components to integrate microphone selection functionality.
- Enhance tests for microphone device handling and environment variable management.

bolt_pet/ui/tray.py

@@ -47,6 +47,7 @@ class PetTray(QSystemTrayIcon):
         on_set_nap: Optional[Callable[[bool], None]] = None,
         on_show_history: Optional[Callable[[], None]] = None,
         on_show_wake_tuner: Optional[Callable[[], None]] = None,
+        on_show_mic_picker: Optional[Callable[[], None]] = None,
         on_reset_voice: Optional[Callable[[], None]] = None,
         parent=None,
     ):
@@ -104,6 +105,11 @@ class PetTray(QSystemTrayIcon):
             tuner_action.triggered.connect(on_show_wake_tuner)
             menu.addAction(tuner_action)
 
+        if on_show_mic_picker is not None:
+            mic_action = QAction("Select microphone…", menu)
+            mic_action.triggered.connect(on_show_mic_picker)
+            menu.addAction(mic_action)
+
         # Only ever enabled while a server-picked voice (speak_as) is in use —
         # it's the way back from "talk like a pirate", which nothing else
         # undoes short of a restart.