fix(qdrant): bind port to loopback only

qdrant has no auth; it was reachable from the whole LAN.

Refs #55 (intent vs. source #63)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docker-compose.yml

@@ -252,7 +252,7 @@ services:
     volumes:
       - qdrant-data:/qdrant/storage
     ports:
-      - "6333:6333"
+      - "127.0.0.1:6333:6333"
     restart: unless-stopped
     networks: [ai-stack]