feat: bundle browser dependencies locally

README.md

@@ -10,6 +10,7 @@ A browser-based photo mapping prototype that reads EXIF/GPS data and shows image
 - Fullscreen photo viewer
 - Timeline view with zoomable time ranges
 - Progressive loading with cancel support
+- Local browser dependency bundle for Leaflet and EXIF parsing
 
 ## Start
 
@@ -23,5 +24,5 @@ npm start
 
 - Photos are not stored on the server.
 - The UI and processing run in the browser where possible.
+- Browser dependencies are installed through npm and copied into `dist/vendor` during `npm run build`; the runtime serves them locally instead of loading third-party CDNs.
 - Future auth can be forwarded by a reverse proxy via HTTP headers.
-