refactor(sidebar): extract typed app/sidebar architecture and split Sidebar into modular components

- Replace `src/App.jsx` with `src/App.tsx` and move route-level UI orchestration into `src/components/app/AppContent.tsx`.
  This separates provider/bootstrap concerns from runtime app layout logic, keeps route definitions minimal, and improves readability of the root app entry.

- Introduce `src/hooks/useProjectsState.ts` to centralize project/session/sidebar state management previously embedded in `App.jsx`.
  This keeps the existing behavior for:
  project loading,
  Cursor session hydration,
  WebSocket `loading_progress` handling,
  additive-update protection for active sessions,
  URL-based session selection,
  sidebar refresh/delete/new-session flows.
  The hook now exposes a typed `sidebarSharedProps` contract and typed handlers used by `AppContent`.

- Introduce `src/hooks/useSessionProtection.ts` for active/processing session lifecycle logic.
  This preserves session-protection behavior while isolating `activeSessions`, `processingSessions`, and temporary-session replacement into a dedicated reusable hook.

- Replace monolithic `src/components/Sidebar.jsx` with typed `src/components/Sidebar.tsx` as a thin orchestrator.
  `Sidebar.tsx` now focuses on wiring controller state/actions, modal visibility, collapsed mode, and version modal behavior instead of rendering every UI branch inline.

- Add `src/hooks/useSidebarController.ts` to encapsulate sidebar interaction/state logic.
  This includes expand/collapse state, inline project/session editing state, project starring/sorting/filtering, lazy session pagination, delete confirmations, rename/delete actions, refresh state, and mobile touch click handling.

- Add strongly typed sidebar domain models in `src/components/sidebar/types.ts` and move sidebar-derived helpers into `src/components/sidebar/utils.ts`.
  Utility coverage now includes:
  session provider normalization,
  session view-model creation (name/time/activity/message count),
  project sorting/filtering,
  task indicator status derivation,
  starred-project persistence and readbacks.

- Split sidebar rendering into focused components under `src/components/sidebar/`:
  `SidebarContent.tsx` for top-level sidebar layout composition.
  `SidebarProjectList.tsx` for project-state branching and project iteration.
  `SidebarProjectsState.tsx` for loading/empty/no-search-result placeholders.
  `SidebarProjectItem.tsx` for per-project desktop/mobile header rendering and actions.
  `SidebarProjectSessions.tsx` for expanded session area, skeletons, pagination, and new-session controls.
  `SidebarSessionItem.tsx` for per-session desktop/mobile item rendering and session actions.
  `SessionProviderIcon.tsx` for provider icon normalization.
  `SidebarHeader.tsx`, `SidebarFooter.tsx`, `SidebarCollapsed.tsx`, and `SidebarModals.tsx` as dedicated typed UI surfaces.
  This keeps rendering responsibilities local and significantly improves traceability.

- Convert shared UI primitives from JSX to TSX:
  `src/components/ui/button.tsx`,
  `src/components/ui/input.tsx`,
  `src/components/ui/badge.tsx`,
  `src/components/ui/scroll-area.tsx`.
  These now provide typed props/variants (`forwardRef` where appropriate) while preserving existing class/behavior.

- Add shared app typings in `src/types/app.ts` for projects/sessions/websocket/loading contracts used by new hooks/components.

- Add global window declarations in `src/types/global.d.ts` for `__ROUTER_BASENAME__`, `refreshProjects`, and `openSettings`, removing implicit `any` usage for global integration points.

- Update `src/main.jsx` to import `App.tsx` and keep app bootstrap consistent with the TS migration.

- Update `src/components/QuickSettingsPanel.jsx` to self-resolve mobile state via `useDeviceSettings` (remove `isMobile` prop dependency), and update `src/components/ChatInterface.jsx` to render `QuickSettingsPanel` directly.
  This reduces prop drilling and keeps quick settings colocated with chat UI concerns.

src/components/app/AppContent.tsx

@@ -0,0 +1,154 @@
+import { useEffect } from 'react';
+import { useNavigate, useParams } from 'react-router-dom';
+import { useTranslation } from 'react-i18next';
+
+import Sidebar from '../Sidebar';
+import MainContent from '../MainContent';
+import MobileNav from '../MobileNav';
+import Settings from '../Settings';
+
+import { useWebSocket } from '../../contexts/WebSocketContext';
+import { useDeviceSettings } from '../../hooks/useDeviceSettings';
+import { useSessionProtection } from '../../hooks/useSessionProtection';
+import { useProjectsState } from '../../hooks/useProjectsState';
+
+export default function AppContent() {
+  const navigate = useNavigate();
+  const { sessionId } = useParams<{ sessionId?: string }>();
+  const { t } = useTranslation('common');
+  const { isMobile } = useDeviceSettings({ trackPWA: false });
+  const { ws, sendMessage, latestMessage } = useWebSocket();
+
+  const {
+    activeSessions,
+    processingSessions,
+    markSessionAsActive,
+    markSessionAsInactive,
+    markSessionAsProcessing,
+    markSessionAsNotProcessing,
+    replaceTemporarySession,
+  } = useSessionProtection();
+
+  const {
+    projects,
+    selectedProject,
+    selectedSession,
+    activeTab,
+    sidebarOpen,
+    isLoadingProjects,
+    isInputFocused,
+    showSettings,
+    settingsInitialTab,
+    externalMessageUpdate,
+    setActiveTab,
+    setSidebarOpen,
+    setIsInputFocused,
+    setShowSettings,
+    openSettings,
+    fetchProjects,
+    sidebarSharedProps,
+  } = useProjectsState({
+    sessionId,
+    navigate,
+    latestMessage,
+    isMobile,
+    activeSessions,
+  });
+
+  useEffect(() => {
+    window.refreshProjects = fetchProjects;
+
+    return () => {
+      if (window.refreshProjects === fetchProjects) {
+        delete window.refreshProjects;
+      }
+    };
+  }, [fetchProjects]);
+
+  useEffect(() => {
+    window.openSettings = openSettings;
+
+    return () => {
+      if (window.openSettings === openSettings) {
+        delete window.openSettings;
+      }
+    };
+  }, [openSettings]);
+
+  return (
+    <div className="fixed inset-0 flex bg-background">
+      {!isMobile ? (
+        <div className="h-full flex-shrink-0 border-r border-border bg-card">
+          <Sidebar {...sidebarSharedProps} />
+        </div>
+      ) : (
+        <div
+          className={`fixed inset-0 z-50 flex transition-all duration-150 ease-out ${sidebarOpen ? 'opacity-100 visible' : 'opacity-0 invisible'
+            }`}
+        >
+          <button
+            className="fixed inset-0 bg-background/80 backdrop-blur-sm transition-opacity duration-150 ease-out"
+            onClick={(event) => {
+              event.stopPropagation();
+              setSidebarOpen(false);
+            }}
+            onTouchStart={(event) => {
+              event.preventDefault();
+              event.stopPropagation();
+              setSidebarOpen(false);
+            }}
+            aria-label={t('versionUpdate.ariaLabels.closeSidebar')}
+          />
+          <div
+            className={`relative w-[85vw] max-w-sm sm:w-80 h-full bg-card border-r border-border transform transition-transform duration-150 ease-out ${sidebarOpen ? 'translate-x-0' : '-translate-x-full'
+              }`}
+            onClick={(event) => event.stopPropagation()}
+            onTouchStart={(event) => event.stopPropagation()}
+          >
+            <Sidebar {...sidebarSharedProps} />
+          </div>
+        </div>
+      )}
+
+      <div className={`flex-1 flex flex-col min-w-0 ${isMobile && !isInputFocused ? 'pb-mobile-nav' : ''}`}>
+        <MainContent
+          selectedProject={selectedProject}
+          selectedSession={selectedSession}
+          activeTab={activeTab}
+          setActiveTab={setActiveTab}
+          ws={ws}
+          sendMessage={sendMessage}
+          latestMessage={latestMessage}
+          isMobile={isMobile}
+          onMenuClick={() => setSidebarOpen(true)}
+          isLoading={isLoadingProjects}
+          onInputFocusChange={setIsInputFocused}
+          onSessionActive={markSessionAsActive}
+          onSessionInactive={markSessionAsInactive}
+          onSessionProcessing={markSessionAsProcessing}
+          onSessionNotProcessing={markSessionAsNotProcessing}
+          processingSessions={processingSessions}
+          onReplaceTemporarySession={replaceTemporarySession}
+          onNavigateToSession={(targetSessionId: string) => navigate(`/session/${targetSessionId}`)}
+          onShowSettings={() => setShowSettings(true)}
+          externalMessageUpdate={externalMessageUpdate}
+        />
+      </div>
+
+      {isMobile && (
+        <MobileNav
+          activeTab={activeTab}
+          setActiveTab={setActiveTab}
+          isInputFocused={isInputFocused}
+        />
+      )}
+
+      <Settings
+        isOpen={showSettings}
+        onClose={() => setShowSettings(false)}
+        projects={projects as any}
+        initialTab={settingsInitialTab}
+      />
+    </div>
+  );
+}