fix: reduce chunk size to 512KB to bypass strict Nginx limits

src/lib/api.ts

@@ -112,7 +112,7 @@ export const api = {
   
   // Storage
   uploadAsset: async (fileBlob) => {
-    const chunkSize = 10 * 1024 * 1024; // 10MB chunks
+    const chunkSize = 512 * 1024; // 512KB chunks to bypass 1MB Nginx limits
     const token = localStorage.getItem('auth_token');
     const authHeaders = token ? { Authorization: `Bearer ${token}` } : {};