feat: persist active tab across reloads via localStorage (#414)

* feat: persist active tab across reloads via localStorage (closes #387)

Remember the last active tab in localStorage instead of always resetting
to 'chat'. Also stop force-switching to chat tab on session change,
so users stay on their preferred tab (shell, git, etc.).

* fix: validate localStorage tab value and add try-catch for restricted contexts

Address CodeRabbit feedback: validate stored activeTab against known
tab IDs before using it, and wrap localStorage access in try-catch
to prevent crashes in restricted environments.

src/hooks/useProjectsState.ts

@@ -101,6 +101,20 @@ const isUpdateAdditive = (
   );
 };
 
+const VALID_TABS: Set<string> = new Set(['chat', 'files', 'shell', 'git', 'tasks', 'preview']);
+
+const readPersistedTab = (): AppTab => {
+  try {
+    const stored = localStorage.getItem('activeTab');
+    if (stored && VALID_TABS.has(stored)) {
+      return stored as AppTab;
+    }
+  } catch {
+    // localStorage unavailable
+  }
+  return 'chat';
+};
+
 export function useProjectsState({
   sessionId,
   navigate,
@@ -111,7 +125,16 @@ export function useProjectsState({
   const [projects, setProjects] = useState<Project[]>([]);
   const [selectedProject, setSelectedProject] = useState<Project | null>(null);
   const [selectedSession, setSelectedSession] = useState<ProjectSession | null>(null);
-  const [activeTab, setActiveTab] = useState<AppTab>('chat');
+  const [activeTab, setActiveTab] = useState<AppTab>(readPersistedTab);
+
+  useEffect(() => {
+    try {
+      localStorage.setItem('activeTab', activeTab);
+    } catch {
+      // Silently ignore storage errors
+    }
+  }, [activeTab]);
+
   const [sidebarOpen, setSidebarOpen] = useState(false);
   const [isLoadingProjects, setIsLoadingProjects] = useState(true);
   const [loadingProgress, setLoadingProgress] = useState<LoadingProgress | null>(null);
@@ -265,8 +288,6 @@ export function useProjectsState({
       return;
     }
 
-    const shouldSwitchTab = !selectedSession || selectedSession.id !== sessionId;
-
     for (const project of projects) {
       const claudeSession = project.sessions?.find((session) => session.id === sessionId);
       if (claudeSession) {
@@ -280,9 +301,6 @@ export function useProjectsState({
         if (shouldUpdateSession) {
           setSelectedSession({ ...claudeSession, __provider: 'claude' });
         }
-        if (shouldSwitchTab) {
-          setActiveTab('chat');
-        }
         return;
       }
 
@@ -298,9 +316,6 @@ export function useProjectsState({
         if (shouldUpdateSession) {
           setSelectedSession({ ...cursorSession, __provider: 'cursor' });
         }
-        if (shouldSwitchTab) {
-          setActiveTab('chat');
-        }
         return;
       }
 
@@ -316,9 +331,6 @@ export function useProjectsState({
         if (shouldUpdateSession) {
           setSelectedSession({ ...codexSession, __provider: 'codex' });
         }
-        if (shouldSwitchTab) {
-          setActiveTab('chat');
-        }
         return;
       }
     }
@@ -341,7 +353,7 @@ export function useProjectsState({
     (session: ProjectSession) => {
       setSelectedSession(session);
 
-      if (activeTab !== 'git' && activeTab !== 'preview') {
+      if (activeTab === 'tasks' || activeTab === 'preview') {
         setActiveTab('chat');
       }