feat: Integrate Firebase Authentication and Firestore

- Added Firebase configuration to Android and iOS projects.
- Created `google-services.json` and `GoogleService-Info.plist` for Firebase setup.
- Implemented `AuthService` for handling user authentication with Firebase.
- Updated `UserProvider` to manage user data with Firestore.
- Refactored `ProfileContent`, `LoginPage`, and `SignUpPage` to use the new authentication service.
- Removed the old `UserService` and replaced it with Firestore-based user management.
- Added Firebase options in `firebase_options.dart` for platform-specific configurations.
- Updated dependencies in `pubspec.yaml` for Firebase packages.

pubspec.lock

@@ -1,6 +1,14 @@
 # Generated by pub
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
+  _flutterfire_internals:
+    dependency: transitive
+    description:
+      name: _flutterfire_internals
+      sha256: "23d16f00a2da8ffa997c782453c73867b0609bd90435195671a54de38a3566df"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.3.62"
   async:
     dependency: transitive
     description:
@@ -41,6 +49,30 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.1.2"
+  cloud_firestore:
+    dependency: "direct main"
+    description:
+      name: cloud_firestore
+      sha256: af66aeffe5943d582c0f655ec860433dbd773ac4a4ffc62c11960b52a18833fe
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.0.2"
+  cloud_firestore_platform_interface:
+    dependency: transitive
+    description:
+      name: cloud_firestore_platform_interface
+      sha256: "494dd3d275a0259e3ba08b442b54e64839b0cf58352a50fe97eb67cacf3bad28"
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.0.2"
+  cloud_firestore_web:
+    dependency: transitive
+    description:
+      name: cloud_firestore_web
+      sha256: "85b7b071c23eecbbbb47a9fbd2cfdb1b6af20f2323663fd90234d91a064f0584"
+      url: "https://pub.dev"
+    source: hosted
+    version: "5.0.2"
   collection:
     dependency: transitive
     description:
@@ -89,6 +121,54 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "7.0.1"
+  firebase_auth:
+    dependency: "direct main"
+    description:
+      name: firebase_auth
+      sha256: "735f857c9363376eeb585e7ba57e67e5f495202cd3f609902b8769795fd823bc"
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.1.0"
+  firebase_auth_platform_interface:
+    dependency: transitive
+    description:
+      name: firebase_auth_platform_interface
+      sha256: "5badda0ea5048ffbb1726169cf5530539490de8055c3bd43f4f9cd5fcef8e556"
+      url: "https://pub.dev"
+    source: hosted
+    version: "8.1.2"
+  firebase_auth_web:
+    dependency: transitive
+    description:
+      name: firebase_auth_web
+      sha256: "07c889d2c56e648ed30225e819801d7e45542747a658d9c385520de35d312dec"
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.0.3"
+  firebase_core:
+    dependency: "direct main"
+    description:
+      name: firebase_core
+      sha256: "4dd96f05015c0dcceaa47711394c32971aee70169625d5e2477e7676c01ce0ee"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.1.1"
+  firebase_core_platform_interface:
+    dependency: transitive
+    description:
+      name: firebase_core_platform_interface
+      sha256: "5873a370f0d232918e23a5a6137dbe4c2c47cf017301f4ea02d9d636e52f60f0"
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.0.1"
+  firebase_core_web:
+    dependency: transitive
+    description:
+      name: firebase_core_web
+      sha256: "61a51037312dac781f713308903bb7a1762a7f92f7bc286a3a0947fb2a713b82"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.1"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -176,6 +256,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.15.6"
+  http:
+    dependency: transitive
+    description:
+      name: http
+      sha256: bb2ce4590bc2667c96f318d68cac1b5a7987ec819351d32b1c987239a815e007
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.5.0"
   http_parser:
     dependency: transitive
     description: