feat: integrate speech-to-text functionality into chat screen with cross-platform permission configuration

ios/Runner/Info.plist

@@ -72,6 +72,10 @@
     <string>We need access to your photo library to set your profile photo.</string>
     <key>NSCameraUsageDescription</key>
     <string>We need access to your camera to take a profile photo.</string>
+    <key>NSMicrophoneUsageDescription</key>
+    <string>We need access to your microphone to enable voice input in chat.</string>
+    <key>NSSpeechRecognitionUsageDescription</key>
+    <string>We use speech recognition to convert your voice to text in chat messages.</string>
     <key>UIApplicationSupportsIndirectInputEvents</key>
     <true/>
     <key>UILaunchStoryboardName</key>