fix: Replace automation stubs with real execution engine

- Replace automation execute stub with run_automation() from execution_engine.py
- Replace agent execute stub with run_agent() from agent_runner.py
- Persist automation settings in system_settings.automation_config JSONB
- Add migration 0034 for automation_config column
- Settings are now saved and loaded from database instead of being ignored

app/plugins/builtins/automation/agent_routes.py

@@ -306,14 +306,38 @@ async def execute_agent(
     db.add(run)
     await db.flush()
 
-    # TODO: Execute agent asynchronously via Agent Runner
-    run.status = "completed"
-    run.completed_at = __import__("datetime").datetime.now(__import__("datetime").timezone.utc)
-    run.duration_seconds = 0.0
-    run.result = "Executed successfully (stub)"
-    await db.flush()
+    # Execute agent via agent runner
+    from app.plugins.builtins.automation.agent_runner import run_agent
 
-    return {"status": "ok", "run_id": str(run.id)}
+    run_id = str(run.id)
+    await db.commit()
+
+    # Run agent
+    result = await run_agent(
+        ctx={"tenant_id": str(tenant_id), "user_id": current_user["user_id"]},
+        agent_id=str(aid),
+        trigger_type="manual",
+        trigger_data={"triggered_by": current_user["user_id"]},
+    )
+
+    # Update run with results
+    from sqlalchemy import update as sa_update
+    from datetime import datetime, timezone
+    now = datetime.now(timezone.utc)
+    async with db.begin():
+        await db.execute(
+            sa_update(AgentRun)
+            .where(AgentRun.id == run.id)
+            .values(
+                status=result.get("status", "completed"),
+                completed_at=now,
+                duration_seconds=0.0,
+                result=result,
+                output_data=result,
+            )
+        )
+
+    return {"status": result.get("status", "ok"), "run_id": run_id, "result": result}
 
 
 @router.post(