fix: use python for chromadb healthcheck

docker-compose.yml

@@ -38,10 +38,11 @@ services:
       - ANONYMIZED_TELEMETRY=FALSE
     restart: unless-stopped
     healthcheck:
-      test: ["CMD", "curl", "-f", "http://localhost:8000/api/v1/heartbeat"]
+      test: ["CMD", "python", "-c", "import urllib.request; urllib.request.urlopen('http://localhost:8000/api/v1/heartbeat')"]
       interval: 15s
       timeout: 5s
       retries: 3
+      start_period: 10s
 
   # ── LLM API proxy ──
   litellm: