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/audio/mic.py

@@ -126,6 +126,27 @@ def record_utterance(
     return pcm
 
 
+def list_input_devices() -> list[dict]:
+    """Every input-capable device sounddevice can see, as
+    {"index", "name", "hostapi"}.
+
+    On Windows in particular, the *same* physical (or virtual) device is
+    normally listed once per host API — MME, DirectSound, WASAPI, WDM-KS —
+    all sharing (or near enough sharing) one name. That makes the name alone
+    an unreliable, often ambiguous way to pick a device (sounddevice matches
+    a string device as a substring and refuses to guess between ties), so the
+    tray's mic picker saves the numeric index instead, which this list exists
+    to let it show alongside a human-readable label."""
+    import sounddevice as sd
+
+    devices = []
+    for index, info in enumerate(sd.query_devices()):
+        if info.get("max_input_channels", 0) > 0:
+            hostapi = sd.query_hostapis(info["hostapi"])["name"]
+            devices.append({"index": index, "name": info["name"], "hostapi": hostapi})
+    return devices
+
+
 def open_input_stream():
     """Real sounddevice input stream, imported lazily so pure-logic tests
     (record_utterance with a fake stream) don't need PortAudio installed."""