chore: remove Airflow completely from the stack

Drop all four Airflow containers (db, init, webserver, scheduler) from the
mlops compose profile, leaving MLflow as the sole mlops service. Remove
AIRFLOW_* env vars, config fields, health-check entries, DAG trigger code
in admin/bench routes, the airflow_dag_run_id schema column, Airflow nav
links and DAG-run links in the admin UI, the two Airflow DAG files
(bench_dag.py, sim_dag.py), and all related docs/ADR references.
Simulations now run exclusively via the subprocess path.

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

services/api/src/db/schema.ts

@@ -117,7 +117,6 @@ export const simRuns = sqliteTable('sim_runs', {
   summaryJson: text('summary_json'),           // JSON: { [policy]: PolicySummary }
   winner: text('winner'),
   personaBreakdownJson: text('persona_breakdown_json'), // JSON: { [persona]: { [policy]: {reward,n} } }
-  airflowDagRunId: text('airflow_dag_run_id'),
   mlflowRunId: text('mlflow_run_id'),
   createdAt: text('created_at').notNull(),
   finishedAt: text('finished_at'),
@@ -142,6 +141,20 @@ export const simEvents = sqliteTable('sim_events', {
   createdAt: text('created_at').notNull(),
 });
 
+// ── Agent outputs (#multi-agent) ─────────────────────────────────────────────
+// One row per (userId, agentId) pre-compute run. The orchestrator reads the
+// freshest non-expired row per agent when assembling the tip prompt.
+export const agentOutputs = sqliteTable('agent_outputs', {
+  id: text('id').primaryKey(),
+  userId: text('user_id').notNull().references(() => users.id),
+  agentId: text('agent_id').notNull(),          // e.g. 'overdue-task'
+  promptText: text('prompt_text').notNull(),     // snippet for orchestrator prompt
+  signalsSnapshot: text('signals_snapshot'),     // JSON: inputs the agent consumed
+  computedAt: text('computed_at').notNull(),     // ISO 8601
+  expiresAt: text('expires_at').notNull(),       // ISO 8601 = computedAt + TTL
+  agentVersion: text('agent_version').notNull(), // bump to invalidate on logic changes
+});
+
 // Admin saved SQL queries.
 export const savedQueries = sqliteTable('saved_queries', {
   id: text('id').primaryKey(),