feat: implement chat history, theme customization, and password management

- Added chat history persistence for active rooms with auto-cleanup on stream end.
- Overhauled Settings page with user profile, theme color picker, and password change.
- Added backend API for user password updates.
- Integrated flutter_launcher_icons and updated app icon to 'H' logo.
- Fixed 'Duplicate keys' bug in danmaku by using UniqueKey and filtering historical messages.
- Updated version to 1.0.0-beta3.5 and author info.

frontend/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: 1.0.0+1
+version: 1.0.0-beta3.5
 
 environment:
   sdk: ^3.11.1
@@ -44,6 +44,7 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
+  flutter_launcher_icons: ^0.13.1
 
   # The "flutter_lints" package below contains a set of recommended lints to
   # encourage good coding practices. The lint set provided by the package is
@@ -52,6 +53,21 @@ dev_dependencies:
   # rules and activating additional ones.
   flutter_lints: ^6.0.0
 
+flutter_launcher_icons:
+  android: "launcher_icon"
+  ios: false
+  image_path: "assets/icon/app_icon.png"
+  min_sdk_android: 21
+  web:
+    generate: true
+    image_path: "assets/icon/app_icon.png"
+    background_color: "#ffffff"
+    theme_color: "#2196F3"
+  windows:
+    generate: true
+    image_path: "assets/icon/app_icon.png"
+    icon_size: 256
+
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec