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/settings-store.test.js

@@ -8,7 +8,9 @@ describe('SettingsStore', () => {
     data = {};
     store = new SettingsStore({
       get: (key) => data[key],
-      set: (key, value) => { data[key] = value; }
+      set: (key, value) => {
+        data[key] = value;
+      },
     });
   });