Aggiunge annunci in-app/sito, contatti e migliora UI copertina sul portale.

Include admin/API/banner nativi, form contatti e reset copertina standard con layout edit più ampio.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/public/admin.css

@@ -582,3 +582,86 @@ body.admin-body {
   color: var(--red) !important;
   font-weight: 600;
 }
+
+.admin-form {
+  display: grid;
+  gap: 0.9rem;
+  max-width: 720px;
+}
+
+.admin-form-row {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 1rem;
+}
+
+.admin-form label {
+  display: block;
+  font-size: 0.8rem;
+  color: var(--muted);
+  margin-bottom: 0.3rem;
+}
+
+.admin-form input:not([type="checkbox"]),
+.admin-form select,
+.admin-form textarea {
+  width: 100%;
+  padding: 0.5rem 0.65rem;
+  border: 1px solid #444;
+  border-radius: 6px;
+  background: #1a1a22;
+  color: #eee;
+  font: inherit;
+}
+
+.admin-form textarea {
+  min-height: 7rem;
+  resize: vertical;
+}
+
+.admin-form-hint {
+  margin: -0.4rem 0 0;
+  font-size: 0.8rem;
+}
+
+.admin-checkbox {
+  display: flex;
+  align-items: center;
+  gap: 0.55rem;
+  color: var(--text);
+  font-size: 0.9rem;
+}
+
+.admin-checkbox input[type="checkbox"] {
+  width: 1rem;
+  height: 1rem;
+}
+
+.admin-channels {
+  margin: 0;
+  padding: 0.85rem 1rem;
+  border: 1px solid #444;
+  border-radius: 8px;
+  display: grid;
+  gap: 0.55rem;
+}
+
+.admin-channels legend {
+  padding: 0 0.35rem;
+  font-size: 0.8rem;
+  color: var(--muted);
+}
+
+.admin-form-actions {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.75rem;
+  margin-top: 0.35rem;
+}
+
+@media (max-width: 720px) {
+  .admin-form-row {
+    grid-template-columns: 1fr;
+  }
+}