fix: add getAppVersion and checkForUpdates stubs to browser mode fallback (#38)

* feat: add About dialog

- Add AboutDialog component with app icon, version, and auto-update status
- Trigger dialog from footer "Text Diff View" button
- Add get-app-version and check-for-updates-now IPC handlers
- Expose getAppVersion() and checkForUpdates() via preload
- Bump version to 1.8.0, update Electron to ^41.1.1

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* chore npmrc

* fix: add getAppVersion and checkForUpdates stubs to browser mode fallback

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: kaishuu0123

src/renderer/src/main.tsx

@@ -13,7 +13,9 @@ if (window.api === undefined) {
     SetThemeName: async (themeName: string): Promise<void> => {
       localStorage.setItem('themeName', themeName)
     },
-    installUpdate: (): void => {}
+    installUpdate: (): void => {},
+    getAppVersion: (): string => '0.0.0',
+    checkForUpdates: (): void => {}
   }
 }