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

backend/main.go

@@ -19,6 +19,7 @@ import (
 	authHandlers "crussell/handlers/auth"
 	"crussell/handlers/bookings"
 	"crussell/handlers/notifications"
+	"crussell/handlers/portfolio"
 	"crussell/handlers/scheduling"
 	"crussell/handlers/services"
 	"crussell/handlers/today"
@@ -85,6 +86,21 @@ func main() {
 		r.Post("/register", authHandlers.RegisterHandler)
 		r.Post("/login", authHandlers.LoginHandler)
 
+		// --- Portfolio Routes (public read, admin write) ---
+		r.Route("/portfolio", func(r chi.Router) {
+			r.Get("/images", portfolio.ListImages)
+			r.Get("/tags", portfolio.ListTags)
+			r.Get("/filters", portfolio.ListFilters)
+			r.Get("/images/{id}", portfolio.GetImage)
+
+			r.Group(func(r chi.Router) {
+				r.Use(mw.RequireAuth)
+				r.Use(mw.RequireAdmin)
+				r.Post("/images", portfolio.UploadImage)
+				r.Delete("/images/{id}", portfolio.DeleteImage)
+			})
+		})
+
 		// --- Scheduling Routes ---
 		r.Route("/scheduling", func(r chi.Router) {
 			// Public GET routes