feat: Implement trip invitation functionality and notification handling

- Added TripInvitationRepository for managing trip invitations.
- Created TripInvitation model with serialization methods.
- Implemented notification payload parser for handling FCM notifications.
- Enhanced NotificationService to manage trip invitations and related actions.
- Updated UserRepository to include user search functionality.
- Modified AuthRepository to store multiple FCM tokens.
- Added tests for trip invitation logic and notification payload parsing.
- Updated pubspec.yaml and pubspec.lock for dependency management.

pubspec.yaml

@@ -16,7 +16,7 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
 # In Windows, build-name is used as the major, minor, and patch parts
 # of the product and file versions while build-number is used as the build suffix.
-version: 2026.1.3+1
+version: 2026.3.2+3
 
 environment:
   sdk: ^3.9.2
@@ -78,6 +78,7 @@ dev_dependencies:
   mockito: ^5.4.4
   build_runner: ^2.4.8
   bloc_test: ^10.0.0
+  firebase_core_platform_interface: ^6.0.2
 
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec