feat: 实现完整国际化（i18n）支持，中英双语实时切换

- 使用 slang 库实现类型安全的国际化，支持 context-free 的 t.xxx 访问
- 新增 l10nBuilder 辅助函数，利用 SignalBuilder 的 dependencies 参数统一处理 locale 响应
- 所有 UI 文本、托盘菜单、对话框、深度链接提示均支持中英双语
- 设置页新增语言切换（跟随系统/中文/English），持久化存储
- 确保 LocaleSettings 在 appLocale 之前更新，避免 effects 时序问题
- 缓存合并后内核配置（lastMergedConfig signal）

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: mapleafgo

build.yaml

@@ -10,3 +10,19 @@ targets:
       reflectable:
         generate_for:
           - no/files
+
+      slang_build_runner:
+        options:
+          base_locale: zh
+          fallback_strategy: base_locale
+          input_directory: lib/i18n
+          input_file_pattern: .i18n.json
+          output_directory: lib/i18n
+          output_file_name: strings.g.dart
+          lazy: false
+          locale_handling: true
+          flutter_integration: true
+          translate_var: t
+          enum_name: AppLocale
+          key_case: camel
+          string_interpolation: dart

lib/data/local/app_settings_storage.dart

@@ -61,6 +61,7 @@ class AppStoredConfig {
   final String? themeMode;
   final String? ignoredVersion;
   final bool autoCheckUpdate;
+  final String? locale;
 
   AppStoredConfig({
     this.selectedFile,
@@ -71,6 +72,7 @@ class AppStoredConfig {
     this.themeMode,
     this.ignoredVersion,
     this.autoCheckUpdate = true,
+    this.locale,
   }) : subUA = subUA ?? Defaults.subUA;
 
   factory AppStoredConfig.fromJson(Map<String, dynamic> json) =>
@@ -86,6 +88,7 @@ class AppStoredConfig {
         themeMode: json['theme-mode'] as String?,
         ignoredVersion: json['ignored-version'] as String?,
         autoCheckUpdate: json['auto-check-update'] as bool? ?? true,
+        locale: json['locale'] as String?,
       );
 
   Map<String, dynamic> toJson() => {
@@ -97,6 +100,7 @@ class AppStoredConfig {
         if (themeMode != null) 'theme-mode': themeMode,
         if (ignoredVersion != null) 'ignored-version': ignoredVersion,
         if (!autoCheckUpdate) 'auto-check-update': autoCheckUpdate,
+        if (locale != null) 'locale': locale,
       };
 
   factory AppStoredConfig.empty() => AppStoredConfig(
@@ -113,6 +117,7 @@ class AppStoredConfig {
     String? themeMode,
     Object? ignoredVersion = _sentinel,
     bool? autoCheckUpdate,
+    String? locale,
   }) =>
       AppStoredConfig(
         selectedFile: selectedFile ?? this.selectedFile,
@@ -125,5 +130,6 @@ class AppStoredConfig {
             ? this.ignoredVersion
             : ignoredVersion as String?,
         autoCheckUpdate: autoCheckUpdate ?? this.autoCheckUpdate,
+        locale: locale ?? this.locale,
       );
 }

lib/i18n/en.i18n.json

@@ -0,0 +1,188 @@
+{
+  "nav": {
+    "home": "Home",
+    "proxies": "Proxies",
+    "profiles": "Profiles",
+    "settings": "Settings"
+  },
+  "home": {
+    "speed": "Speed",
+    "connections": "Connections",
+    "connectionCount": "connections",
+    "memory": "Memory Usage",
+    "trafficTotal": "Total Traffic",
+    "outboundMode": "Outbound Mode",
+    "proxyMode": "Proxy Mode",
+    "systemProxy": "System Proxy",
+    "waitingCore": "Waiting for core...",
+    "pleaseAddProfile": "Add a profile first",
+    "enable": "Enable",
+    "copy": "Copy"
+  },
+  "mode": {
+    "rule": "Rule",
+    "global": "Global",
+    "direct": "Direct"
+  },
+  "proxies": {
+    "title": "Proxies",
+    "sort": "Sort",
+    "speedTest": "Speed Test",
+    "empty": "No Proxies",
+    "emptyHint": "Proxies will appear here after adding a profile",
+    "sortTitle": "Sort By",
+    "sortDefault": "Default",
+    "sortByName": "By Name",
+    "sortByDelay": "By Delay",
+    "expandGroups": "Expand Groups",
+    "selectGroup": "Select Group",
+    "switchFailed": "Failed to switch proxy: $error"
+  },
+  "profiles": {
+    "title": "Profiles",
+    "add": "Add",
+    "addSubscription": "Add Profile",
+    "fromFile": "From File",
+    "fromUrl": "From URL",
+    "edit": "Edit",
+    "remove": "Remove",
+    "update": "Update",
+    "updating": "Updating...",
+    "confirmDelete": "Confirm Delete",
+    "confirmDeleteMessage": "Delete \"$name\"?",
+    "configExists": "Profile \"$name\" already exists",
+    "fileCopyFailed": "File copy failed: $error",
+    "urlValidationFailed": "URL validation failed: $error",
+    "updateFailed": "Update failed: $error",
+    "importFailed": "Import failed: $error",
+    "configValidationFailed": "Config validation failed: $validation",
+    "subscriptionExists": "Subscription already exists",
+    "inputUrl": "Enter Profile URL",
+    "pleaseInput": "Please enter",
+    "name": "Name",
+    "updateIntervalHours": "Update Interval (hours)",
+    "empty": "No Profiles",
+    "emptyHint": "Tap the button below to add a profile",
+    "copy": "Copy"
+  },
+  "settings": {
+    "title": "Settings",
+    "sectionCore": "Core",
+    "proxyService": "Proxy Service",
+    "proxyServiceDesc": "Enable HTTP/SOCKS5 mixed proxy port",
+    "allowLan": "Allow LAN",
+    "allowLanDesc": "Allow other LAN devices to use this proxy",
+    "port": "Port",
+    "portDesc": "Local port for proxy service",
+    "portValidationError": "Enter a port between 1-65535",
+    "notSet": "Not set",
+    "ipv6": "IPv6",
+    "ipv6Desc": "Support IPv6 for proxy connections",
+    "outboundMode": "Outbound Mode",
+    "outboundModeDesc": "Control traffic routing strategy",
+    "clashApi": "Clash API",
+    "clashApiDesc": "Expose proxy status and control interface",
+    "apiAddress": "API Address",
+    "logLevel": "Log Level",
+    "logLevelDesc": "Lower level = more detailed, use Debug for troubleshooting",
+    "logDebug": "Debug",
+    "logInfo": "Info",
+    "logWarning": "Warning",
+    "logError": "Error",
+    "sectionGeneral": "General",
+    "subUserAgent": "Subscription User-Agent",
+    "subUaDialogTitle": "Subscription User-Agent",
+    "subUaDialogDesc": "User-Agent for subscription updates",
+    "inputUa": "Enter User-Agent",
+    "defaultValue": "Default",
+    "delayTestUrl": "Delay Test URL",
+    "delayTestUrlDesc": "Target URL for latency testing",
+    "ruleSetProxy": "Rule-Set Proxy",
+    "ruleSetProxyDesc": "Proxy address for downloading rule-set",
+    "autoCheckUpdate": "Check for Updates on Startup",
+    "autoCheckUpdateDesc": "Automatically check for new versions on startup",
+    "sectionAppearance": "Appearance",
+    "theme": "Theme",
+    "themeDesc": "Change app appearance",
+    "themeSystem": "System Default",
+    "themeLight": "Light",
+    "themeDark": "Dark",
+    "language": "Language",
+    "languageDesc": "Change app display language",
+    "languageSystem": "System Default",
+    "sectionOther": "Other",
+    "about": "About",
+    "aboutDesc": "Version info and related links"
+  },
+  "about": {
+    "title": "About",
+    "officialWebsite": "Website",
+    "sourceRepo": "Source Code",
+    "kernelVersion": "Kernel Version",
+    "loading": "Loading...",
+    "version": "Version",
+    "newVersionFound": "Update Available",
+    "versionInfo": "Current: $current\nLatest: $latest",
+    "ignore": "Ignore",
+    "goDownload": "Download",
+    "removeElevation": "Remove Elevation",
+    "removeElevationConfirm": "Confirm Remove Elevation",
+    "removeElevationDesc": "This will remove the TUN elevation service and restart the core in built-in mode (TUN unavailable). You will need to re-elevate next time you use TUN.",
+    "removeElevationWinDesc": "Remove Windows service and switch to built-in core",
+    "removeElevationMacDesc": "Remove elevated core and switch to built-in core",
+    "elevationRemoved": "Elevation removed, switched to built-in core",
+    "operationFailed": "Operation failed",
+    "exportLog": "Export Log",
+    "logNotInitialized": "Log not initialized",
+    "logFileNotExist": "Log file not found",
+    "logExported": "Log exported",
+    "exportFailed": "Export failed",
+    "easterEgg": "You found me!"
+  },
+  "dialogs": {
+    "error": "Error",
+    "cancel": "Cancel",
+    "confirm": "OK",
+    "delete": "Delete",
+    "import": "Import",
+    "copy": "Copy"
+  },
+  "tray": {
+    "showWindow": "Show Window",
+    "tunMode": "TUN Mode",
+    "systemProxy": "System Proxy",
+    "exit": "Exit"
+  },
+  "core": {
+    "connectionFailed": "Core connection failed: $error",
+    "initTimeout": "Core initialization timed out",
+    "initFailed": "Core initialization failed: $error",
+    "reconnectCore": "Reconnect Core",
+    "restartCore": "Restart Core",
+    "reconnectMessage": "Core is disconnected. Try reconnecting?",
+    "restartMessage": "Restart core service?",
+    "reconnect": "Reconnect",
+    "restart": "Restart",
+    "coreState": "Core Status",
+    "coreDisconnected": "Core disconnected, tap to reconnect",
+    "modeSwitchFailed": "Failed to switch mode: $error",
+    "elevationFailed": "Elevation failed, please retry"
+  },
+  "deepLink": {
+    "importSubscription": "Import Profile",
+    "confirmImport": "Import profile \"$name\"?",
+    "confirmImportNoName": "Import this profile?",
+    "importSuccess": "Profile imported successfully",
+    "importFailed": "Profile import failed: $error"
+  },
+  "startup": {
+    "newVersionFound": "Update Available",
+    "currentAndLatest": "Current: $current\nLatest: $latest",
+    "ignoreThisTime": "Dismiss",
+    "ignoreThisVersion": "Ignore This Version",
+    "goDownload": "Download"
+  },
+  "common": {
+    "close": "Close"
+  }
+}