Portfolio: add filtering, URL sharing, and improved tag input

- Add category filters with dynamic counts that reduce as filters
  applied
- Add ?filter[category]=value URL params for filterable links
- Add ?img= timestamp param that bypasses filters to show specific image
- Update URL when opening/navigating/closing modal for shareable links
- Backend: add /api/portfolio/filters endpoint with filter logic
- Backend: add timestamp lookup fallback for GetImage endpoint
  Frontend:
- Portfolio page: filter dropdowns, keyboard nav, mobile improvements
- ImageUpload: live tag suggestions from API, arrow/Tab navigation,
  confirmation modal before upload, mobile-optimized touch targets
- Add scrollbar-hide utility and fix filter dropdown overflow
- Move Clear all button, add vertical separator on desktop

.env.example

@@ -16,9 +16,11 @@ JWT_SECRET_KEY="a-very-secret-key-that-should-be-in-env"
 # Dev: Uses local Rustfs container (see compose.yml)
 # Prod: Use Cloudflare R2 credentials
 S3_ENDPOINT=http://localhost:9000
-S3_ACCESS_KEY=minioadmin
-S3_SECRET_KEY=minioadmin
+S3_PUBLIC_URL=http://192.168.1.135:9000
+S3_ACCESS_KEY=rustfsadmin
+S3_SECRET_KEY=rustfsadmin
 S3_BUCKET=crussell
+AWS_REGION=eu-west-2
 
 # Prod: Uncomment and fill these for R2
 # R2_ENDPOINT=https://<account-id>.r2.cloudflarestorage.com