feat: implement offline fonts support (v0.1.4)

- Add local font files to public/fonts directory
- Replace Google Fonts CDN with local @font-face declarations
- Include both regular and italic variants for preview fonts
- Remove unused editor italic fonts to reduce bundle size
- App now fully functional offline without external dependencies
- Total font bundle: ~22.8 MB (10 font files)

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "Nextcloud Notes",
-  "version": "0.1.3",
+  "version": "0.1.4",
   "identifier": "com.davidrelich.nextcloud-notes",
   "build": {
     "beforeDevCommand": "npm run dev",