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

apps/test/features/chat/chat_bloc_test.dart

@@ -194,7 +194,7 @@ void main() {
         service.onEvent(
           ToolCallStartEvent(
             toolCallId: 'tc_1',
-            toolCallName: 'create_calendar_event',
+            toolCallName: 'back.mutate_calendar_event',
           ),
         );
       },
@@ -203,7 +203,7 @@ void main() {
           (s) {
             final item = s.items.first;
             return item is ToolCallItem &&
-                item.toolName == 'create_calendar_event' &&
+                item.toolName == 'back.mutate_calendar_event' &&
                 item.status == ToolCallStatus.pending;
           },
           'has pending tool call',
@@ -220,7 +220,7 @@ void main() {
           ToolCallItem(
             id: 'tc_1',
             callId: 'tc_1',
-            toolName: 'navigate_to_route',
+            toolName: 'front.navigate_to_route',
             args: {'target': '/calendar/dayweek', '__nonce': 'nonce_1'},
             status: ToolCallStatus.executing,
             timestamp: DateTime.now(),
@@ -241,5 +241,40 @@ void main() {
         isA<ChatState>().having((s) => s.items.isEmpty, 'items empty', true),
       ],
     );
+
+    blocTest<ChatBloc, ChatState>(
+      'toolCallResult with ui in payload.result adds ToolResultItem',
+      build: () => chatBloc,
+      seed: () => ChatState(
+        items: [
+          ToolCallItem(
+            id: 'tc_2',
+            callId: 'tc_2',
+            toolName: 'back.mutate_calendar_event',
+            args: {'operation': 'create'},
+            status: ToolCallStatus.executing,
+            timestamp: DateTime.now(),
+            sender: MessageSender.ai,
+          ),
+        ],
+      ),
+      act: (bloc) {
+        service.onEvent(
+          ToolCallResultEvent(
+            messageId: 'msg_tool_2',
+            toolCallId: 'tc_2',
+            content:
+                '{"result":{"type":"calendar_operation.v1","version":"v1","data":{"operation":"delete","ok":true,"message":"done"},"actions":[]}}',
+          ),
+        );
+      },
+      expect: () => [
+        isA<ChatState>().having(
+          (s) => s.items.first is ToolResultItem,
+          'first item is ToolResultItem',
+          true,
+        ),
+      ],
+    );
   });
 }