fix(batch): resolve pandoc path handling and include-subfolders option

- Normalize pandoc command parsing with path.basename() to support bundled binary paths
- Use bundled pandoc binary in convertWithPandoc instead of relying on PATH
- Forward includeSubfolders checkbox state from renderer to main process
- Add pandoc availability check before batch conversion
- Re-enable Start button when batch conversion completes
- Clean up obsolete dist build artifact causing test snapshot warning
- Bump version to 4.4.4

tests/event-bus.test.js

@@ -48,7 +48,9 @@ describe('EventBus', () => {
 
   test('handler errors are caught and logged, not thrown', () => {
     const errorSpy = jest.spyOn(console, 'error').mockImplementation(() => {});
-    bus.on('bad:event', () => { throw new Error('boom'); });
+    bus.on('bad:event', () => {
+      throw new Error('boom');
+    });
     expect(() => bus.emit('bad:event', {})).not.toThrow();
     expect(errorSpy).toHaveBeenCalled();
     errorSpy.mockRestore();