fix: separate 400/500 error cases in feedback proxy route

app/api/feedback/route.ts

@@ -3,8 +3,12 @@ import { NextRequest, NextResponse } from 'next/server'
 const API_BASE_URL = process.env.API_BASE_URL || process.env.NEXT_PUBLIC_API_BASE_URL
 
 export async function POST(req: NextRequest) {
+  let body: unknown
   try {
-    const body = await req.json()
+    body = await req.json()
+  } catch {
+    return NextResponse.json({ error: 'Invalid request' }, { status: 400 })
+  }
 
   const ip =
     req.headers.get('x-forwarded-for')?.split(',')[0]?.trim() ??
@@ -12,10 +16,11 @@ export async function POST(req: NextRequest) {
     'unknown'
   const userAgent = req.headers.get('user-agent') ?? 'unknown'
 
+  try {
     const res = await fetch(`${API_BASE_URL}/api/v1/feedback`, {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ ...body, ipAddress: ip, userAgent }),
+      body: JSON.stringify({ ...(body as object), ipAddress: ip, userAgent }),
       cache: 'no-store',
     })
 
@@ -28,6 +33,6 @@ export async function POST(req: NextRequest) {
     return NextResponse.json({ ok: true })
   } catch (e) {
     console.error('[/api/feedback] proxy error:', e)
-    return NextResponse.json({ error: 'Invalid request' }, { status: 400 })
+    return NextResponse.json({ error: 'Service unavailable' }, { status: 500 })
   }
 }