feat: refactor input source handling and add audio input service

lib/services/audio_input_service.dart

@@ -0,0 +1,49 @@
+import 'package:flutter/services.dart';
+import 'package:permission_handler/permission_handler.dart';
+import 'dart:developer' as developer;
+
+class AudioInputService {
+  static final AudioInputService _instance = AudioInputService._internal();
+  factory AudioInputService() => _instance;
+  AudioInputService._internal();
+
+  static const _methodChannel = MethodChannel('org.noxylva.lbjconsole/audio_input');
+  
+  bool _isListening = false;
+  bool get isListening => _isListening;
+
+  Future<bool> startListening() async {
+    if (_isListening) return true;
+
+    var status = await Permission.microphone.status;
+    if (!status.isGranted) {
+      status = await Permission.microphone.request();
+      if (!status.isGranted) {
+        developer.log('Microphone permission denied', name: 'AudioInput');
+        return false;
+      }
+    }
+
+    try {
+      await _methodChannel.invokeMethod('start');
+      _isListening = true;
+      developer.log('Audio input started', name: 'AudioInput');
+      return true;
+    } on PlatformException catch (e) {
+      developer.log('Failed to start audio input: ${e.message}', name: 'AudioInput');
+      return false;
+    }
+  }
+
+  Future<void> stopListening() async {
+    if (!_isListening) return;
+    
+    try {
+      await _methodChannel.invokeMethod('stop');
+      _isListening = false;
+      developer.log('Audio input stopped', name: 'AudioInput');
+    } catch (e) {
+      developer.log('Error stopping audio input: $e', name: 'AudioInput');
+    }
+  }
+}