feat: session manger (#867)

* feat: init session manger

* feat: persist selected app to localStorage

- Save app selection when switching providers
- Restore last selected app on page load

* feat: persist current view to localStorage

- Save view selection when switching tabs
- Restore last selected view on page load

* styles: update ui

* feat: Improve macOS Terminal activation and refactor Kitty launch to use  command with user's default shell.

* fix: session view

* feat: toc

* feat: Implement FlexSearch for improved session search functionality.

* feat: Redesign session manager search and filter UI for a more compact and dynamic experience.

* refactor: modularize session manager by extracting components and utility functions into dedicated files.

* feat: Enhance session terminal launching with support for iTerm2, Ghostty, WezTerm, and Alacritty, including UI and custom configuration options.

* feat: Conditionally render terminal selection and resume session buttons only on macOS.

src/components/AppSwitcher.tsx

@@ -10,6 +10,7 @@ interface AppSwitcherProps {
 }
 
 const ALL_APPS: AppId[] = ["claude", "codex", "gemini", "opencode"];
+const STORAGE_KEY = "cc-switch-last-app";
 
 export function AppSwitcher({
   activeApp,
@@ -19,6 +20,7 @@ export function AppSwitcher({
 }: AppSwitcherProps) {
   const handleSwitch = (app: AppId) => {
     if (app === activeApp) return;
+    localStorage.setItem(STORAGE_KEY, app);
     onSwitch(app);
   };
   const iconSize = 20;