feat: add Codec2 voice messages over LoRa mesh (iOS/macOS only)

Push-to-talk voice messaging using the Codec2 ultra-low-bitrate speech
codec, transmitted as V: prefixed packets over the existing MeshCore
LoRa mesh pipeline.

Voice recording UI (long-press send button or + menu) is gated behind
Platform.isIOS || Platform.isMacOS since the `record` package only
supports microphone capture on those platforms in this build.

Key changes:
- VoiceRecorderService: streams 8kHz mono PCM chunks via `record` package
- VoicePlayerService: decodes Codec2 bytes to WAV and plays via audioplayers
- VoiceCodecService: async Codec2 encode/decode in background isolates
- VoiceProvider: reassembles multi-packet sessions, drives playback
- VoiceMessageBubble: shows packet progress, play/stop controls
- MessagesProvider: detects V: prefix, routes to VoiceProvider
- MessagesTab: PTT long-press gesture + recording indicator (iOS/macOS)
- Message model: isVoice + voiceId fields for session tracking
- Auto-selects codec mode from radio bandwidth (700C/1200/1300 bps)
- codec2_flutter + meshcore_client switched from path to git deps

pubspec.lock

@@ -25,6 +25,62 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.13.0"
+  audioplayers:
+    dependency: "direct main"
+    description:
+      name: audioplayers
+      sha256: "5441fa0ceb8807a5ad701199806510e56afde2b4913d9d17c2f19f2902cf0ae4"
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.5.1"
+  audioplayers_android:
+    dependency: transitive
+    description:
+      name: audioplayers_android
+      sha256: "60a6728277228413a85755bd3ffd6fab98f6555608923813ce383b190a360605"
+      url: "https://pub.dev"
+    source: hosted
+    version: "5.2.1"
+  audioplayers_darwin:
+    dependency: transitive
+    description:
+      name: audioplayers_darwin
+      sha256: "0811d6924904ca13f9ef90d19081e4a87f7297ddc19fc3d31f60af1aaafee333"
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.3.0"
+  audioplayers_linux:
+    dependency: transitive
+    description:
+      name: audioplayers_linux
+      sha256: f75bce1ce864170ef5e6a2c6a61cd3339e1a17ce11e99a25bae4474ea491d001
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.2.1"
+  audioplayers_platform_interface:
+    dependency: transitive
+    description:
+      name: audioplayers_platform_interface
+      sha256: "0e2f6a919ab56d0fec272e801abc07b26ae7f31980f912f24af4748763e5a656"
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.1.1"
+  audioplayers_web:
+    dependency: transitive
+    description:
+      name: audioplayers_web
+      sha256: "1c0f17cec68455556775f1e50ca85c40c05c714a99c5eb1d2d57cc17ba5522d7"
+      url: "https://pub.dev"
+    source: hosted
+    version: "5.1.1"
+  audioplayers_windows:
+    dependency: transitive
+    description:
+      name: audioplayers_windows
+      sha256: "4048797865105b26d47628e6abb49231ea5de84884160229251f37dfcbe52fd7"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.2.1"
   bluez:
     dependency: transitive
     description:
@@ -73,6 +129,15 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.1.2"
+  codec2_flutter:
+    dependency: "direct main"
+    description:
+      path: "."
+      ref: HEAD
+      resolved-ref: "0d3009f2626cd64232b7e19741f9ac45b0f01385"
+      url: "https://github.com/dz0ny/codec2_flutter.git"
+    source: git
+    version: "0.1.0"
   collection:
     dependency: transitive
     description:
@@ -162,7 +227,7 @@ packages:
     source: hosted
     version: "1.3.3"
   ffi:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: ffi
       sha256: "289279317b4b16eb2bb7e271abccd4bf84ec9bdcbe999e278a94b804f5630418"
@@ -593,8 +658,8 @@ packages:
     dependency: "direct main"
     description:
       path: "."
-      ref: main
-      resolved-ref: ca34662abe4ef511bcb6b3b6fd2c5f648fee62fe
+      ref: HEAD
+      resolved-ref: b0126d3941117d4ae2948047834f1136324a26fd
       url: "https://github.com/dz0ny/meshcore_client.git"
     source: git
     version: "0.1.0"
@@ -870,6 +935,70 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "6.1.5+1"
+  record:
+    dependency: "direct main"
+    description:
+      name: record
+      sha256: d5b6b334f3ab02460db6544e08583c942dbf23e3504bf1e14fd4cbe3d9409277
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.2.0"
+  record_android:
+    dependency: transitive
+    description:
+      name: record_android
+      sha256: "94783f08403aed33ffb68797bf0715b0812eb852f3c7985644c945faea462ba1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.5.1"
+  record_ios:
+    dependency: transitive
+    description:
+      name: record_ios
+      sha256: "8df7c136131bd05efc19256af29b2ba6ccc000ccc2c80d4b6b6d7a8d21a3b5a9"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.2.0"
+  record_linux:
+    dependency: transitive
+    description:
+      name: record_linux
+      sha256: c31a35cc158cd666fc6395f7f56fc054f31685571684be6b97670a27649ce5c7
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.3.0"
+  record_macos:
+    dependency: transitive
+    description:
+      name: record_macos
+      sha256: "084902e63fc9c0c224c29203d6c75f0bdf9b6a40536c9d916393c8f4c4256488"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.2.1"
+  record_platform_interface:
+    dependency: transitive
+    description:
+      name: record_platform_interface
+      sha256: "8a81dbc4e14e1272a285bbfef6c9136d070a47d9b0d1f40aa6193516253ee2f6"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.5.0"
+  record_web:
+    dependency: transitive
+    description:
+      name: record_web
+      sha256: "7e9846981c1f2d111d86f0ae3309071f5bba8b624d1c977316706f08fc31d16d"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.3.0"
+  record_windows:
+    dependency: transitive
+    description:
+      name: record_windows
+      sha256: "223258060a1d25c62bae18282c16783f28581ec19401d17e56b5205b9f039d78"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.7"
   rxdart:
     dependency: transitive
     description: