fix: default replicate previews to portrait ratio

.memory/worklog.json

@@ -1587,6 +1587,20 @@
       "message": "auto-save 2026-05-20 17:11 (~2)",
       "hash": "36c93cd",
       "files_changed": 2
+    },
+    {
+      "ts": "2026-05-20T17:13:15+08:00",
+      "type": "commit",
+      "message": "fix: preserve primary image aspect ratio",
+      "hash": "288b695",
+      "files_changed": 2
+    },
+    {
+      "ts": "2026-05-20T17:17:06+08:00",
+      "type": "commit",
+      "message": "auto-save 2026-05-20 17:17 (~2)",
+      "hash": "1325a73",
+      "files_changed": 2
     }
   ]
 }

src/app/page.tsx

@@ -34,6 +34,10 @@ function projectTitle(session: GenSession) {
   return session.characterSpec?.name || session.prompt || '未命名项目';
 }
 
+function defaultPrimaryAspectRatio(session: GenSession) {
+  return session.inputMode === 'replicate' || session.inputMode === 'extend' ? '2 / 3' : '1 / 1';
+}
+
 function imageSourcesForSession(session: GenSession) {
   const uploaded = session.uploadedImages?.map(image => ({
     url: image.url,
@@ -90,11 +94,11 @@ function ProjectBrief({ session }: { session: GenSession }) {
   const generatedAssets = (session.packs ?? []).reduce((sum, pack) => sum + pack.assets.length, 0);
   const totalSlots = packSlotTotal();
   const [previewOpen, setPreviewOpen] = useState(false);
-  const [primaryAspectRatio, setPrimaryAspectRatio] = useState('1 / 1');
+  const [primaryAspectRatio, setPrimaryAspectRatio] = useState(defaultPrimaryAspectRatio(session));
 
   useEffect(() => {
-    setPrimaryAspectRatio('1 / 1');
-  }, [primaryImage?.url]);
+    setPrimaryAspectRatio(defaultPrimaryAspectRatio(session));
+  }, [primaryImage?.url, session.inputMode]);
 
   return (
     <section className="project-brief-panel">