feat(realestate): 내부 인증 + naver 워커 targets 엔드포인트 + nginx internal 블록

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EqCYBhvTcdeCTUDX3RhWx9

realestate-lab/app/auth.py

@@ -0,0 +1,11 @@
+"""Windows naver-fetch 워커 → NAS realestate-lab 내부 엔드포인트 인증."""
+import os
+from fastapi import Header, HTTPException
+
+
+def verify_internal_key(x_internal_key: str = Header(...)):
+    expected = os.getenv("INTERNAL_API_KEY")
+    if not expected:
+        raise HTTPException(401, "INTERNAL_API_KEY not configured on server")
+    if x_internal_key != expected:
+        raise HTTPException(401, "Invalid X-Internal-Key")