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>

services/api/src/index.ts

@@ -15,7 +15,7 @@ import { integrationsRouter } from './routes/integrations.js';
 import { recommenderRouter } from './routes/recommender.js';
 import { userRouter } from './routes/user.js';
 import { pushRouter } from './routes/push.js';
-import { adminRouter } from './routes/admin.js';
+import { adminRouter, adminInternalRouter } from './routes/admin.js';
 import { mkdir } from 'fs/promises';
 import { dirname } from 'path';
 import { requireAuth } from './middleware/session.js';
@@ -65,6 +65,7 @@ app.use('/api', recommenderRouter);
 app.use('/api/user', userRouter);
 app.use('/api/push', pushRouter);
 app.use('/api/admin', adminRouter);
+app.use('/api/admin', adminInternalRouter);
 
 app.use('/api/ml', requireAuth as any, requireAdmin as any, async (req: Request, res: Response) => {
   const mlUrl = config.ML_SERVING_URL;