feat: enhance WelcomeDialog, export dialogs, GitStatusPanel, add CommandPalette, FindReplaceBar, and new converter dialogs

- WelcomeDialog: add quick start, feature showcase, keyboard shortcuts, recent files, version display
- ExportDocxDialog/ExportHtmlDialog/ExportPdfDialog: add header/footer, paper size, margin controls
- GitStatusPanel: full staging/unstaging, discard, commit workflow
- CommandPalette: fuzzy command search with keyboard navigation
- FindReplaceBar: find/replace with regex, case, whole-word options
- New dialogs: BatchMediaConverterDialog, HeaderFooterDialog, PdfEditorDialog, UniversalConverterDialog
- Tests: comprehensive coverage for all new/updated components

tests/component/sidebar/GitStatusPanel.test.tsx

@@ -12,8 +12,30 @@ vi.mock('@/lib/ipc', () => ({
   },
 }));
 
+vi.mock('@/lib/toast', () => ({
+  toast: {
+    success: vi.fn(),
+    error: vi.fn(),
+    info: vi.fn(),
+    warning: vi.fn(),
+    promise: vi.fn(),
+    dismiss: vi.fn(),
+  },
+}));
+
 import { ipc } from '@/lib/ipc';
 
+const mockGitStage = vi.fn();
+const mockGitCommit = vi.fn();
+
+Object.defineProperty(window, 'electronAPI', {
+  value: {
+    gitStage: mockGitStage,
+    gitCommit: mockGitCommit,
+  },
+  writable: true,
+});
+
 describe('GitStatusPanel', () => {
   beforeEach(() => {
     localStorage.clear();
@@ -54,7 +76,6 @@ describe('GitStatusPanel', () => {
     });
     useFileStore.setState({ rootPath: '/project' } as any);
     render(<GitStatusPanel />);
-    // The helper text appears in a <p> element distinct from the error heading
     expect(
       await screen.findByText('Not a git repository, or git not installed.')
     ).toBeInTheDocument();
@@ -72,4 +93,65 @@ describe('GitStatusPanel', () => {
     await userEvent.click(row);
     expect(openFile).toHaveBeenCalledWith('/project/a.md');
   });
+
+  it('shows stage and commit UI when files are changed', async () => {
+    (ipc.file.gitStatus as any).mockResolvedValueOnce({
+      ok: true,
+      data: [{ filePath: '/project/a.md', status: 'modified' }],
+    });
+    useFileStore.setState({ rootPath: '/project' } as any);
+    render(<GitStatusPanel />);
+    expect(await screen.findByText('Select All')).toBeInTheDocument();
+    expect(screen.getByText('Stage Selected')).toBeInTheDocument();
+    expect(screen.getByText('Stage All')).toBeInTheDocument();
+    expect(screen.getByTestId('git-commit-input')).toBeInTheDocument();
+    expect(screen.getByTestId('git-commit-button')).toBeInTheDocument();
+  });
+
+  it('selects and deselects files via checkboxes and select all', async () => {
+    (ipc.file.gitStatus as any).mockResolvedValue({
+      ok: true,
+      data: [
+        { filePath: '/project/a.md', status: 'modified' },
+        { filePath: '/project/b.md', status: 'added' },
+      ],
+    });
+    useFileStore.setState({ rootPath: '/project' } as any);
+    render(<GitStatusPanel />);
+    const selectAllBtn = await screen.findByText('Select All');
+    await userEvent.click(selectAllBtn);
+    expect(screen.getByText('Deselect All')).toBeInTheDocument();
+    await userEvent.click(screen.getByText('Deselect All'));
+    expect(screen.getByText('Select All')).toBeInTheDocument();
+  });
+
+  it('stages selected files', async () => {
+    mockGitStage.mockResolvedValueOnce(undefined);
+    (ipc.file.gitStatus as any).mockResolvedValue({
+      ok: true,
+      data: [{ filePath: '/project/a.md', status: 'modified' }],
+    });
+    useFileStore.setState({ rootPath: '/project' } as any);
+    render(<GitStatusPanel />);
+    const checkbox = await screen.findByTestId('git-status-checkbox');
+    await userEvent.click(checkbox);
+    const stageBtn = screen.getByTestId('git-stage-selected');
+    await userEvent.click(stageBtn);
+    expect(mockGitStage).toHaveBeenCalledWith(['/project/a.md']);
+  });
+
+  it('commits with message', async () => {
+    mockGitCommit.mockResolvedValueOnce(undefined);
+    (ipc.file.gitStatus as any).mockResolvedValue({
+      ok: true,
+      data: [{ filePath: '/project/a.md', status: 'modified' }],
+    });
+    useFileStore.setState({ rootPath: '/project' } as any);
+    render(<GitStatusPanel />);
+    const input = await screen.findByTestId('git-commit-input');
+    await userEvent.type(input, 'fix typo');
+    const commitBtn = screen.getByTestId('git-commit-button');
+    await userEvent.click(commitBtn);
+    expect(mockGitCommit).toHaveBeenCalledWith('fix typo');
+  });
 });