feat: Refactor LLM router and integrate health check endpoint

- Simplified LLM call logic in llm_router.py, removing tool adapter complexity and enhancing error handling.
- Added health check endpoint to main.py for system status verification.
- Cleaned up router.py by removing unused imports and commented-out code, streamlining the structure.
- Updated docker-compose.yml to unify services under a single Lyra container, enhancing deployment simplicity.
- Created Dockerfile for unified container setup, including both Relay and Cortex services.
- Added QUICKSTART.md for improved onboarding and usage instructions.
- Implemented start.sh script to manage service startup and health checks.

cortex/main.py

@@ -13,4 +13,9 @@ app.add_middleware(
     allow_headers=["*"],
 )
 
+# Health check endpoint
+@app.get("/_health")
+async def health_check():
+    return {"status": "ok"}
+
 app.include_router(cortex_router)