feat(simulate): MLflow tracking, Airflow DAG integration, health checks for mlflow/airflow

- sim_runs schema: add judge_mode, n_policies, airflow_dag_run_id, mlflow_run_id columns
- admin health endpoint: add mlflow + airflow checks (Basic auth for Airflow API)
- admin nav: add Simulations page link; rename section label
- runner.py: optional MLflow experiment tracking; multi-policy support
- sim_dag.py: Airflow DAG for offline sim pipeline
- admin simulate page + API client methods for sim runs
- shared-types tsconfig: exclude test files from build

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/shared-types/tsconfig.json

@@ -4,5 +4,6 @@
     "outDir": "dist",
     "rootDir": "src"
   },
-  "include": ["src"]
+  "include": ["src"],
+  "exclude": ["src/__tests__", "**/*.test.ts"]
 }