fix(growth): fix add button and form submission

- Fix + Add button to properly open form (was closing immediately)
- Add error handling and saving state to form
- Add visual feedback (Saving... text, error messages)
- Clear form state properly when opening

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/growth/page.tsx

@@ -64,6 +64,8 @@ export default function GrowthPage() {
 
   // Chart state
   const [chartMetric, setChartMetric] = useState<"weight" | "height" | "head">("weight");
+  const [saving, setSaving] = useState(false);
+  const [saveError, setSaveError] = useState<string | null>(null);
 
   // Goals state
   const [goal, setGoal] = useState<Goal>({});
@@ -101,8 +103,14 @@ export default function GrowthPage() {
   };
 
   const handleAdd = async () => {
-    if (!childId || (!weight && !height && !headCircumference)) return;
-    await fetch("/api/growth", {
+    if (!childId || (!weight && !height && !headCircumference)) {
+      setSaveError("Please enter at least one measurement");
+      return;
+    }
+    setSaving(true);
+    setSaveError(null);
+    try {
+      const res = await fetch("/api/growth", {
         method: "POST",
         headers: { "Content-Type": "application/json" },
         body: JSON.stringify({
@@ -113,12 +121,25 @@ export default function GrowthPage() {
           headCircumferenceCm: headCircumference ? parseFloat(headCircumference) : null,
         }),
       });
+      if (!res.ok) {
+        const err = await res.json();
+        setSaveError(err.error || "Failed to save");
+        return;
+      }
       resetForm();
       fetchGrowthData();
+    } catch (e: any) {
+      setSaveError(e.message || "Failed to save");
+    } finally {
+      setSaving(false);
+    }
   };
 
   const handleEdit = async (id: string) => {
-    await fetch("/api/growth", {
+    setSaving(true);
+    setSaveError(null);
+    try {
+      const res = await fetch("/api/growth", {
         method: "PUT",
         headers: { "Content-Type": "application/json" },
         body: JSON.stringify({
@@ -129,9 +150,19 @@ export default function GrowthPage() {
           headCircumferenceCm: headCircumference ? parseFloat(headCircumference) : null,
         }),
       });
+      if (!res.ok) {
+        const err = await res.json();
+        setSaveError(err.error || "Failed to update");
+        return;
+      }
       setEditingId(null);
       resetForm();
       fetchGrowthData();
+    } catch (e: any) {
+      setSaveError(e.message || "Failed to update");
+    } finally {
+      setSaving(false);
+    }
   };
 
   const handleDelete = async (id: string) => {
@@ -330,7 +361,7 @@ export default function GrowthPage() {
           <button onClick={() => setShowGoals(!showGoals)} className="p-2 text-sm bg-gray-200 dark:bg-gray-700 rounded-lg" title="Set goals">
             🎯
           </button>
-          <button onClick={() => { setShowAdd(!showAdd); setEditingId(null); resetForm(); }} className="p-2 bg-rose-400 text-white rounded-lg">
+          <button onClick={() => { setShowAdd(!showAdd); setEditingId(null); setWeight(""); setHeight(""); setHeadCircumference(""); setMeasuredAt(new Date().toISOString().split("T")[0]); }} className="p-2 bg-rose-400 text-white rounded-lg">
             + Add
           </button>
         </div>
@@ -547,6 +578,9 @@ export default function GrowthPage() {
       {showAdd && (
         <div className="mx-4 mb-4 p-4 bg-white dark:bg-gray-800 rounded-xl space-y-3">
           <h3 className="font-semibold">{editingId ? "Edit Record" : "Add New Measurement"}</h3>
+          {saveError && (
+            <div className="p-2 bg-red-100 dark:bg-red-900 text-red-600 rounded-lg text-sm">{saveError}</div>
+          )}
           <input
             type="date"
             value={measuredAt}
@@ -580,16 +614,16 @@ export default function GrowthPage() {
           <div className="flex gap-2">
             {editingId ? (
               <>
-                <button onClick={() => handleEdit(editingId)} className="flex-1 p-3 bg-rose-400 text-white rounded-xl">
-                  Update
+                <button onClick={() => handleEdit(editingId)} disabled={saving} className="flex-1 p-3 bg-rose-400 text-white rounded-xl disabled:opacity-50">
+                  {saving ? "Saving..." : "Update"}
                 </button>
                 <button onClick={resetForm} className="flex-1 p-3 bg-gray-200 dark:bg-gray-700 rounded-xl">
                   Cancel
                 </button>
               </>
             ) : (
-              <button onClick={handleAdd} className="w-full p-3 bg-rose-400 text-white rounded-xl">
-                Save
+              <button onClick={() => handleAdd()} disabled={saving} className="w-full p-3 bg-rose-400 text-white rounded-xl disabled:opacity-50">
+                {saving ? "Saving..." : "Save"}
               </button>
             )}
           </div>