fix(flutter): pin livekit_client to ^2.6.4, upgrade device_info_plus to ^12.3.0

livekit_client 2.3.1+hotfix.1 removed the `subscribe` parameter from Timeouts,
causing build failure. Pinning to 2.6.4 (which has subscribe) and bumping
device_info_plus to ^12.3.0 as required by livekit_client >=2.6.0.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

it0_app/pubspec.lock

@@ -282,7 +282,7 @@ packages:
     source: hosted
     version: "0.7.12"
   device_info_plus:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: device_info_plus
       sha256: "4df8babf73058181227e18b08e6ea3520cf5fc5d796888d33b7cb0f33f984b7c"
@@ -322,7 +322,7 @@ packages:
     source: hosted
     version: "0.3.1"
   equatable:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: equatable
       sha256: "3e0141505477fd8ad55d6eb4e7776d3fe8430be8e497ccb1521370c3f21a3e2b"

it0_app/pubspec.yaml

@@ -40,7 +40,7 @@ dependencies:
   file_picker: ^8.0.0
 
   # Voice
-  livekit_client: ^2.3.0
+  livekit_client: ^2.6.4
   record: ^6.0.0
   flutter_tts: ^4.0.0
   sherpa_onnx: ^1.12.25
@@ -70,7 +70,7 @@ dependencies:
   crypto: ^3.0.3
 
   # Telemetry
-  device_info_plus: ^10.1.0
+  device_info_plus: ^12.3.0
   equatable: ^2.0.5
 
 dev_dependencies: