feat(agent): add voice input capability and standardize tool naming

- Add voice recording with transcribe endpoint (ASR) for multimodal input
- Android: add RECORD_AUDIO and INTERNET permissions
- Refactor tool naming: frontend tools use 'front.' prefix, backend tools use 'back.'
- Migrate calendar tools: create_calendar_event -> back.mutate/list/delete events
- Add calendar_event_list.v1 and calendar_operation.v1 UI card types
- Update all Flutter and Python tests to match new tool naming conventions
- Add record package dependency for voice recording

backend/tests/e2e/test_agent_live_flow.py

@@ -355,7 +355,7 @@ async def test_agent_live_image_calendar_tool_persistence() -> None:
         else:
             payload = json.loads(str(downloaded))
 
-        assert payload["toolName"] == "back.create_calendar_event"
+        assert payload["toolName"] == "back.mutate_calendar_event"
     finally:
         if uploaded_paths:
             try: