fix: legacy QR URLs without '?' (productid in path) redirect to /t/CODE (new tag 97 now scans); preview page photo portrait aspect; Preview button on user tags list; admin photo form = preview + standalone Upload button (removed URL TextInput — no duplicate, no stale placeholder)

frontend/internal/handlers/legacy.go

@@ -0,0 +1,21 @@
+package handlers
+
+import (
+	"net/http"
+	"strings"
+)
+
+// LegacyNotFound handles old printed QR URLs of the form
+// https://where-woof.com/x=5&productid=CODE (no '?' before productid —
+// the whole thing lands in the path). Redirects to /t/CODE.
+func (a *App) LegacyNotFound(w http.ResponseWriter, r *http.Request) {
+	path := r.URL.Path
+	if i := strings.Index(path, "productid="); i >= 0 {
+		code := path[i+len("productid="):]
+		if code != "" {
+			http.Redirect(w, r, "/t/"+code, http.StatusFound)
+			return
+		}
+	}
+	http.NotFound(w, r)
+}