fix(plan): narrow mode in EditForm IIFE and style plan-banner

src/admin/components/PlanCellModal.tsx

@@ -100,6 +100,17 @@ function EditForm(props: Props) {
   const [submitting, setSubmitting] = useState(false);
   const [confirmDelete, setConfirmDelete] = useState(false);
 
+  // Narrow mode to the kinds EditForm actually handles. The call site in
+  // PlanCellModal only passes "create" | "edit-range" | "edit-override" but
+  // the parameter type is the full union, so we narrow explicitly here.
+  if (
+    mode.kind !== "create" &&
+    mode.kind !== "edit-range" &&
+    mode.kind !== "edit-override"
+  ) {
+    return null;
+  }
+
   const isOverride = mode.kind === "edit-override";
 
   const initial = (() => {
@@ -123,6 +134,7 @@ function EditForm(props: Props) {
         note: mode.range.note,
       };
     }
+    // mode.kind === "edit-override" (narrowed above)
     return {
       date_from: mode.date,
       date_to: mode.date,

src/admin/plan.css

@@ -123,3 +123,22 @@
   margin-bottom: 12px;
   flex-wrap: wrap;
 }
+
+.plan-banner {
+  padding: 10px 14px;
+  margin-bottom: 16px;
+  background: var(--info-soft, #eff6ff);
+  border: 1px solid var(--info-light, #bfdbfe);
+  border-left: 4px solid var(--info, #3b82f6);
+  border-radius: var(--border-radius-sm, 6px);
+  color: var(--info, #1e40af);
+  font-size: 14px;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+
+.plan-banner code {
+  background: transparent;
+  padding: 0;
+}