In-app Persian (Farsi) localization with runtime language switching (#43)

* fix: add missing language code persistence to settings store and models

- Add WhiteDnsLanguage object with En/Fa constants to WhiteDnsModels.kt
- Add languageCode field to WhiteDnsSettings data class with default En
- Add normalizeLanguageCode function for language code validation
- Call normalizeLanguageCode in syncSelectedConnectionProfileFields
- Add KeyLanguageCode constant to WhiteDnsSettingsStore
- Load languageCode from preferences in WhiteDnsSettingsStore.load()
- Save languageCode to preferences in WhiteDnsSettingsStore.save()

This fixes the issue where language changes weren't persisting across app restarts.

* feat(i18n): add language switcher to App Settings dialog

- Add LanguageModeSegmentedControl composable (English/فارسی toggle)
- Update AppSettingsDialog to show language picker below theme picker
- Update HeaderCard to accept and thread languageCode/onLanguageCodeChange
- Update all 4 HeaderCard call sites to wire language setting
- Update WhiteDnsTheme to accept languageCode and inject RTL layout direction
- Update MainActivity to pass languageCode to WhiteDnsTheme

* feat(i18n): implement CompositionLocal string localization for key UI elements

- Create WhiteDnsStrings.kt interface with EnglishStrings and PersianStrings
- Add LocalWhiteDnsStrings and WhiteDnsL10n to WhiteDnsTheme.kt
- Inject correct strings based on languageCode into CompositionLocalProvider
- Replace key hardcoded visible strings with WhiteDnsL10n references:
  - Bottom tab labels (Profiles/Connect/Scan/Logs)
  - Connect button (CONNECT/CONNECTING/STOP)
  - App Settings dialog title and CLOSE button
  - Theme/Language field labels and option labels
  - Battery background banner text and action button
  - Profile tab headers (Connection/Resolver/Setting)
  - Parallel Test toggle label

* feat(i18n): localize connection mode, section headers, and server route strings

- Localize Mode field label (Mode / حالت)
- Localize connection mode buttons (Proxy Mode/Full VPN → حالت پروکسی/VPN کامل)
- Localize Connection/Resolver section headers
- Localize 'Server route missing' in all occurrences
- Fix ConnectionModeSegmentedControl to use localized option labels

* feat(i18n): localize default profile names and remaining English strings

- Add setupDefaultConnection/Resolver/Advanced strings to substitute
  localized labels when the user has not renamed the default profiles
- Wire id-based label override into setup card, home selectors,
  connection info card, advanced profile controls, and the three
  profile list rows (connection, resolver, settings)
- Localize the resolver row summary (count + SELECTED suffix) and
  the settings row MODIFIED/SELECTED status suffixes via new
  profileStatusModified and resolverProfileSummary entries

* chore: drop local-only files from branch

Author: Danialsamadi

app/src/main/java/shop/whitedns/client/MainActivity.kt

@@ -44,7 +44,10 @@ class MainActivity : ComponentActivity() {
         enableEdgeToEdge()
 
         setContent {
-            WhiteDnsTheme(themeMode = viewModel.uiState.settings.themeMode) {
+            WhiteDnsTheme(
+                themeMode = viewModel.uiState.settings.themeMode,
+                languageCode = viewModel.uiState.settings.languageCode,
+            ) {
                 val context = LocalContext.current
                 var shouldConnectAfterNotificationPermission by rememberSaveable { mutableStateOf(false) }
                 val vpnPermissionLauncher = rememberLauncherForActivityResult(

app/src/main/java/shop/whitedns/client/model/WhiteDnsModels.kt

@@ -238,6 +238,7 @@ data class WhiteDnsSettings(
     val connectionMode: String = "proxy",
     val protocolType: String = "SOCKS5",
     val themeMode: String = WhiteDnsThemeMode.System,
+    val languageCode: String = WhiteDnsLanguage.En,
     val resolverText: String = "",
     val listenIp: String = "127.0.0.1",
     val listenPort: String = "10886",
@@ -454,6 +455,11 @@ object WhiteDnsThemeMode {
     const val Dark = "dark"
 }
 
+object WhiteDnsLanguage {
+    const val En = "en"
+    const val Fa = "fa"
+}
+
 data class WhiteDnsScanState(
     val sessionId: String = "",
     val status: String = WhiteDnsScanStatus.Idle,
@@ -696,6 +702,7 @@ fun WhiteDnsSettings.syncSelectedConnectionProfileFields(): WhiteDnsSettings {
     val selected = profiles.firstOrNull { it.id == selectedConnectionProfileId } ?: profiles.first()
     val selectedConnectionMode = normalizeConnectionMode(connectionMode)
     val selectedThemeMode = normalizeThemeMode(themeMode)
+    val selectedLanguageCode = normalizeLanguageCode(languageCode)
     val modeSyncedProfiles = profiles.map { profile ->
         if (profile.id == selected.id) {
             profile.copy(connectionMode = selectedConnectionMode)
@@ -725,6 +732,7 @@ fun WhiteDnsSettings.syncSelectedConnectionProfileFields(): WhiteDnsSettings {
         customServerEncryptionMethod = selected.customServerEncryptionMethod,
         connectionMode = selectedConnectionMode,
         themeMode = selectedThemeMode,
+        languageCode = selectedLanguageCode,
         splitTunnelMode = normalizeSplitTunnelMode(splitTunnelMode),
         splitTunnelPackages = normalizePackageNames(splitTunnelPackages),
     )
@@ -1487,6 +1495,13 @@ private fun normalizeThemeMode(raw: String): String {
     }
 }
 
+private fun normalizeLanguageCode(raw: String): String {
+    return when (raw) {
+        WhiteDnsLanguage.Fa -> WhiteDnsLanguage.Fa
+        else -> WhiteDnsLanguage.En
+    }
+}
+
 private fun normalizePackageNames(raw: List<String>): List<String> {
     return raw
         .asSequence()

app/src/main/java/shop/whitedns/client/model/WhiteDnsSettingsStore.kt

@@ -83,6 +83,7 @@ class WhiteDnsSettingsStore(
             connectionMode = legacyConnectionMode,
             protocolType = preferences.getString(KeyProtocolType, defaults.protocolType) ?: defaults.protocolType,
             themeMode = preferences.getString(KeyThemeMode, defaults.themeMode) ?: defaults.themeMode,
+            languageCode = preferences.getString(KeyLanguageCode, defaults.languageCode) ?: defaults.languageCode,
             resolverText = if (resolverText == LegacyDefaultResolverText) defaults.resolverText else resolverText,
             listenIp = preferences.getString(KeyListenIp, defaults.listenIp) ?: defaults.listenIp,
             listenPort = preferences.getString(KeyListenPort, defaults.listenPort) ?: defaults.listenPort,
@@ -230,6 +231,7 @@ class WhiteDnsSettingsStore(
             .putString(KeyConnectionMode, normalizedSettings.connectionMode)
             .putString(KeyProtocolType, normalizedSettings.protocolType)
             .putString(KeyThemeMode, normalizedSettings.themeMode)
+            .putString(KeyLanguageCode, normalizedSettings.languageCode)
             .putString(KeyResolverText, normalizedSettings.resolverText)
             .putString(KeyListenIp, normalizedSettings.listenIp)
             .putString(KeyListenPort, normalizedSettings.listenPort)
@@ -692,6 +694,7 @@ class WhiteDnsSettingsStore(
         const val KeyConnectionMode = "connection_mode"
         const val KeyProtocolType = "protocol_type"
         const val KeyThemeMode = "theme_mode"
+        const val KeyLanguageCode = "language_code"
         const val KeyResolverText = "resolver_text"
         const val KeyListenIp = "listen_ip"
         const val KeyListenPort = "listen_port"