refactor: remove immersive mode toggle remnants — always enabled

Immersive mode was already hardcoded to true with a no-op setter.
Clean up all dead code:
- Remove isImmersive param from useImmersiveMode hook
- Remove immersiveMode/setImmersiveMode from useSettingsState
- Remove toggle from SettingsPage and SettingsAppearanceTab
- Remove sync read/write of immersiveMode setting
- Remove i18n keys for the removed toggle
- Simplify App.tsx conditionals

Kept: useImmersiveMode hook (core logic), CSS classes (fade overlay),
sync type field (backward compat), storage key.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

App.tsx

@@ -201,7 +201,6 @@ function App({ settings }: { settings: SettingsState }) {
     sessionLogsDir,
     sessionLogsFormat,
     reapplyCurrentTheme,
-    immersiveMode,
     workspaceFocusStyle,
   } = settings;
 
@@ -358,7 +357,6 @@ function App({ settings }: { settings: SettingsState }) {
   }, [activeTabId, currentTerminalTheme, hostById, sessionById, themeById, workspaceById]);
 
   useImmersiveMode({
-    isImmersive: immersiveMode,
     activeTabId,
     activeTerminalTheme,
     restoreOriginalTheme: reapplyCurrentTheme,
@@ -1312,7 +1310,7 @@ function App({ settings }: { settings: SettingsState }) {
   }, []);
 
   return (
-    <div className={cn("flex flex-col h-screen text-foreground font-sans netcatty-shell", immersiveMode && activeTerminalTheme && "immersive-transition")} onContextMenu={handleRootContextMenu}>
+    <div className={cn("flex flex-col h-screen text-foreground font-sans netcatty-shell", activeTerminalTheme && "immersive-transition")} onContextMenu={handleRootContextMenu}>
       <TopTabs
         theme={resolvedTheme}
         hosts={hosts}
@@ -1333,7 +1331,7 @@ function App({ settings }: { settings: SettingsState }) {
         onToggleTheme={handleToggleTheme}
         onOpenSettings={handleOpenSettings}
         onSyncNow={handleSyncNowManual}
-        isImmersiveActive={immersiveMode && activeTerminalTheme !== null}
+        isImmersiveActive={activeTerminalTheme !== null}
         onStartSessionDrag={setDraggingSessionId}
         onEndSessionDrag={handleEndSessionDrag}
         onReorderTabs={reorderTabs}

application/i18n/locales/en.ts

@@ -234,9 +234,6 @@ const en: Messages = {
   'settings.appearance.themeColor.desc': 'Pick a preset palette for each theme',
   'settings.appearance.themeColor.light': 'Light palette',
   'settings.appearance.themeColor.dark': 'Dark palette',
-  'settings.appearance.immersiveMode': 'Immersive Mode',
-  'settings.appearance.immersiveMode.desc':
-    'When enabled, the UI chrome (tab bar, sidebar, status bar) adapts its colors to match the active terminal theme for a visually cohesive experience.',
   'settings.appearance.customCss': 'Custom CSS',
   'settings.appearance.customCss.desc':
     'Add custom CSS to personalize the app appearance. Changes apply immediately.',

application/i18n/locales/zh-CN.ts

@@ -218,9 +218,6 @@ const zhCN: Messages = {
   'settings.appearance.themeColor.desc': '为浅色与深色主题选择预设配色',
   'settings.appearance.themeColor.light': '浅色主题',
   'settings.appearance.themeColor.dark': '深色主题',
-  'settings.appearance.immersiveMode': '沉浸模式',
-  'settings.appearance.immersiveMode.desc':
-    '启用后，UI 外观（标签栏、侧边栏、状态栏）会自动适配当前终端主题的配色，营造视觉一体化的沉浸体验。',
   'settings.appearance.customCss': '自定义 CSS',
   'settings.appearance.customCss.desc': '使用自定义 CSS 个性化界面，修改会立即生效。',
   'settings.appearance.customCss.placeholder':

application/state/useImmersiveMode.ts

@@ -151,12 +151,10 @@ function removeImmersiveStyle() {
 // ---------------------------------------------------------------------------
 
 export function useImmersiveMode({
-  isImmersive,
   activeTabId,
   activeTerminalTheme,
   restoreOriginalTheme,
 }: {
-  isImmersive: boolean;
   activeTabId: string;
   activeTerminalTheme: TerminalTheme | null;
   restoreOriginalTheme: () => void;
@@ -170,14 +168,14 @@ export function useImmersiveMode({
 
   // APPLY: useLayoutEffect — runs before paint, O(1) Map lookup, single DOM write
   useLayoutEffect(() => {
-    if (isImmersive && isTerminalTab && activeTerminalTheme) {
+    if (isTerminalTab && activeTerminalTheme) {
       const fp = themeFingerprint(activeTerminalTheme);
       if (appliedFpRef.current === fp) return;
       overrideActiveRef.current = true;
       appliedFpRef.current = fp;
       applyImmersiveStyle(getImmersiveCss(activeTerminalTheme), activeTerminalTheme.type === 'dark', activeTerminalTheme.colors.background);
     }
-  }, [isImmersive, isTerminalTab, activeTerminalTheme]);
+  }, [isTerminalTab, activeTerminalTheme]);
 
   // RESTORE: useEffect — runs after paint, with fade overlay
   useEffect(() => {
@@ -198,7 +196,7 @@ export function useImmersiveMode({
     });
     const fallback = setTimeout(() => { if (overlay.parentNode) overlay.remove(); }, 400);
     return () => { clearTimeout(fallback); if (overlay.parentNode) overlay.remove(); };
-  }, [isImmersive, isTerminalTab, activeTerminalTheme, restoreOriginalTheme]);
+  }, [isTerminalTab, activeTerminalTheme, restoreOriginalTheme]);
 
   // Cleanup on unmount
   useEffect(() => {

application/state/usePortForwardingAutoStart.ts

@@ -116,7 +116,7 @@ export const usePortForwardingAutoStart = ({
     return () => {
       setReconnectCallback(null);
     };
-  }, []);
+  }, [resolveEffectiveHost]);
 
   // Auto-start rules on app launch
   useEffect(() => {
@@ -196,5 +196,5 @@ export const usePortForwardingAutoStart = ({
     };
 
     void runAutoStart();
-  }, [hosts, identities, isHostAuthReady, keys]);
+  }, [hosts, identities, isHostAuthReady, keys, resolveEffectiveHost]);
 };

application/state/useSettingsState.ts

@@ -125,7 +125,7 @@ const applyThemeTokens = (
   accentOverride: string,
 ) => {
   const root = window.document.documentElement;
-  // If immersive mode is active (style tag present), it owns the dark/light class — don't override
+  // If immersive override is active (style tag present), it owns the dark/light class — don't override
   if (!document.getElementById('netcatty-immersive-override')) {
     root.classList.remove('light', 'dark');
     root.classList.add(resolvedTheme);
@@ -340,11 +340,6 @@ export const useSettingsState = () => {
     }
   }, []);
 
-  // Immersive mode is always enabled — the toggle has been removed from settings
-  const immersiveMode = true;
-  const setImmersiveMode = useCallback((_enabled: boolean) => {
-    // no-op: immersive mode is always on
-  }, []);
 
   const setSftpTransferConcurrency = useCallback((value: number) => {
     const clamped = Math.max(1, Math.min(16, Math.round(value)));
@@ -651,7 +646,7 @@ export const useSettingsState = () => {
     sftpDoubleClickBehavior, sftpAutoSync, sftpShowHiddenFiles,
     sftpUseCompressedUpload, sftpAutoOpenSidebar, sftpDefaultViewMode,
     editorWordWrap, sessionLogsEnabled, sessionLogsDir, sessionLogsFormat,
-    globalHotkeyEnabled, autoUpdateEnabled, immersiveMode,
+    globalHotkeyEnabled, autoUpdateEnabled,
   });
   settingsSnapshotRef.current = {
     theme, lightUiThemeId, darkUiThemeId, accentMode, customAccent,
@@ -660,7 +655,7 @@ export const useSettingsState = () => {
     sftpDoubleClickBehavior, sftpAutoSync, sftpShowHiddenFiles,
     sftpUseCompressedUpload, sftpAutoOpenSidebar, sftpDefaultViewMode,
     editorWordWrap, sessionLogsEnabled, sessionLogsDir, sessionLogsFormat,
-    globalHotkeyEnabled, autoUpdateEnabled, immersiveMode,
+    globalHotkeyEnabled, autoUpdateEnabled,
   };
 
   // Listen for storage changes from other windows (cross-window sync)
@@ -1220,8 +1215,6 @@ export const useSettingsState = () => {
     setGlobalHotkeyEnabled,
     rehydrateAllFromStorage,
     reapplyCurrentTheme,
-    immersiveMode,
-    setImmersiveMode,
     workspaceFocusStyle,
     setWorkspaceFocusStyle,
     // Opaque version that changes when any synced setting changes, used by useAutoSync.
@@ -1232,7 +1225,7 @@ export const useSettingsState = () => {
       terminalThemeId, terminalFontFamilyId, terminalFontSize, terminalSettings,
       customKeyBindings, editorWordWrap,
       sftpDoubleClickBehavior, sftpAutoSync, sftpShowHiddenFiles, sftpUseCompressedUpload, sftpAutoOpenSidebar, sftpDefaultViewMode,
-      customThemes, immersiveMode, workspaceFocusStyle,
+      customThemes, workspaceFocusStyle,
     ]),
   };
 };

application/syncPayload.ts

@@ -42,7 +42,6 @@ import {
   STORAGE_KEY_SFTP_AUTO_OPEN_SIDEBAR,
   STORAGE_KEY_SFTP_GLOBAL_BOOKMARKS,
   STORAGE_KEY_CUSTOM_THEMES,
-  STORAGE_KEY_IMMERSIVE_MODE,
   STORAGE_KEY_SHOW_RECENT_HOSTS,
 } from '../infrastructure/config/storageKeys';
 
@@ -171,9 +170,6 @@ export function collectSyncableSettings(): SyncPayload['settings'] {
   const globalBookmarks = localStorageAdapter.read<SftpBookmark[]>(STORAGE_KEY_SFTP_GLOBAL_BOOKMARKS);
   if (globalBookmarks && Array.isArray(globalBookmarks)) settings.sftpGlobalBookmarks = globalBookmarks;
 
-  // Immersive mode
-  const immersive = localStorageAdapter.readString(STORAGE_KEY_IMMERSIVE_MODE);
-  if (immersive === 'true' || immersive === 'false') settings.immersiveMode = immersive === 'true';
 
   const showRecent = localStorageAdapter.readBoolean(STORAGE_KEY_SHOW_RECENT_HOSTS);
   if (showRecent != null) settings.showRecentHosts = showRecent;
@@ -240,8 +236,7 @@ function applySyncableSettings(settings: NonNullable<SyncPayload['settings']>):
   // SFTP Bookmarks (global only)
   if (settings.sftpGlobalBookmarks != null) localStorageAdapter.write(STORAGE_KEY_SFTP_GLOBAL_BOOKMARKS, settings.sftpGlobalBookmarks);
 
-  // Immersive mode
-  if (settings.immersiveMode != null) localStorageAdapter.writeString(STORAGE_KEY_IMMERSIVE_MODE, String(settings.immersiveMode));
+  // Immersive mode (legacy — always enabled, ignore incoming value)
   if (settings.showRecentHosts != null) localStorageAdapter.writeBoolean(STORAGE_KEY_SHOW_RECENT_HOSTS, settings.showRecentHosts);
 }
 

components/SettingsPage.tsx

@@ -155,10 +155,6 @@ const SettingsPageContent: React.FC<{ settings: SettingsState }> = ({ settings }
     const { updateState, checkNow, installUpdate, openReleasePage, startDownload, isUpdateDemoMode } = useUpdateCheck({ autoUpdateEnabled: settings.autoUpdateEnabled });
     const [activeTab, setActiveTab] = useState("application");
     const [mountedTabs, setMountedTabs] = useState(() => new Set(["application"]));
-    const isImmersive = settings.immersiveMode;
-    const toggleImmersive = useCallback(() => {
-        settings.setImmersiveMode(!isImmersive);
-    }, [settings, isImmersive]);
 
     useEffect(() => {
         notifyRendererReady();
@@ -286,8 +282,6 @@ const SettingsPageContent: React.FC<{ settings: SettingsState }> = ({ settings }
                             setUiLanguage={settings.setUiLanguage}
                             customCSS={settings.customCSS}
                             setCustomCSS={settings.setCustomCSS}
-                            isImmersive={isImmersive}
-                            onToggleImmersive={toggleImmersive}
                         />
                     )}
 

components/settings/tabs/SettingsAppearanceTab.tsx

@@ -27,8 +27,6 @@ export default function SettingsAppearanceTab(props: {
   setUiLanguage: (language: string) => void;
   customCSS: string;
   setCustomCSS: (css: string) => void;
-  isImmersive?: boolean;
-  onToggleImmersive?: () => void;
 }) {
   const { t } = useI18n();
   const availableUIFonts = useAvailableUIFonts();
@@ -49,8 +47,6 @@ export default function SettingsAppearanceTab(props: {
     setUiLanguage,
     customCSS,
     setCustomCSS,
-    isImmersive: _isImmersive,
-    onToggleImmersive: _onToggleImmersive,
   } = props;
 
   const [showRecentHosts, setShowRecentHosts] = useStoredBoolean(