fix: use same-origin API calls in production + HEAD method support for Next.js prefetch

backend/app/main.py

@@ -101,7 +101,7 @@ if os.path.exists(FRONTEND_BUILD_DIR):
     if os.path.exists(static_dir):
         app.mount("/static", StaticFiles(directory=static_dir), name="static")
 
-    @app.get("/{full_path:path}")
+    @app.api_route("/{full_path:path}", methods=["GET", "HEAD"])
     async def serve_frontend(full_path: str):
         """Serve Next.js static export — tries exact file, then .html, then index.html."""
         # Try exact file path
@@ -114,6 +114,11 @@ if os.path.exists(FRONTEND_BUILD_DIR):
         if os.path.isfile(html_path):
             return FileResponse(html_path)
 
+        # Try .txt for RSC payloads (Next.js uses .txt for RSC data)
+        txt_path = os.path.join(FRONTEND_BUILD_DIR, f"{full_path}.txt")
+        if os.path.isfile(txt_path):
+            return FileResponse(txt_path)
+
         # Try as directory index
         index_path = os.path.join(FRONTEND_BUILD_DIR, full_path, "index.html")
         if os.path.isfile(index_path):

frontend/src/lib/api.ts

@@ -3,7 +3,7 @@
  * Handles authentication headers and base URL configuration.
  */
 
-const API_BASE = process.env.NEXT_PUBLIC_API_URL || "http://localhost:7860";
+const API_BASE = process.env.NEXT_PUBLIC_API_URL || "";
 
 interface FetchOptions extends RequestInit {
   token?: string;