fix(frontend): Handle non-JSON API responses safely in ActivityFeed

frontend/components/feed/activity-feed.tsx

@@ -23,11 +23,25 @@ export function ActivityFeed() {
     const [loading, setLoading] = useState(true)
 
     useEffect(() => {
-        fetch(`${getApiUrl()}/feed/`)
-            .then(res => res.json())
-            .then(setFeed)
-            .catch(console.error)
-            .finally(() => setLoading(false))
+        const fetchFeed = async () => {
+            try {
+                const res = await fetch(`${getApiUrl()}/feed/`)
+                if (!res.ok) {
+                    const text = await res.text()
+                    console.error('Feed API error:', res.status, text)
+                    setFeed([]) // Fallback to empty
+                    return
+                }
+                const data = await res.json()
+                setFeed(data)
+            } catch (error) {
+                console.error('Failed to fetch feed:', error)
+                setFeed([])
+            } finally {
+                setLoading(false)
+            }
+        }
+        fetchFeed()
     }, [])
 
     if (loading) return <div>Loading activity...</div>