feat(integration): prepaid billing, engine UI, credits console, direct tasks, v2 final

- Prepaid credit system: org wallet, debit on usage, chat gate, admin credit console
- Engine UI: /manager, /tasks, /tasks/[id], /workforce, /dashboard, /traces pages
- Direct task creation (HTTP POST /tasks, MCP tasks_create) at pending_manager_review
- Pause/resume/cancel/answer actions in engine API and UI
- Employee cap (7 per org default), review pipeline guard (active reviewer required)
- Scheduler: wide window prevents org starvation; archived employees excluded from cap
- Tenant isolation: project-id cross-org 404, engine never uses another tenant's sandbox
- Order route fix: manager built with pipeline states + employee profiles
- Contract extension: ModelGrantPort.get_org_policy with DefaultOrgPolicy
- Engine event types in @agy/contracts (task.step, task.gate, run.log, run.tool, team.changed)
- api-engine.ts typed client; api-credit.ts client
- Alembic migration c4d5e6f7a8b9: prepaid credit + engine UI tables
- 859 tests passed, 1 skipped; ruff/mypy/tsc/eslint/vitest all green

Refs: PLAN-v2.md §9 (T1–T43), todo-v2-final.md

apps/api/tests/test_error_log.py

@@ -429,25 +429,27 @@ async def test_a_failed_task_run_is_persisted_with_its_tenant(
     seeded, client: AsyncClient, session_factory, monkeypatch
 ):
     """A task that cannot run is a tenant-visible problem, so the row must name
-    the organization — otherwise nobody can find it in the console."""
+    the organization — otherwise nobody can find it in the console.
+
+    Decision D-D: the legacy drain is the path under test, so the task is a pre-v2 row
+    (no pipeline state); a task made over HTTP is the engine's now.
+    """
     from app.application.services.workforce_service import WorkforceService
     from app.workers.ai_runtime import AiRuntimeWorker
-    from tests.test_workers import _make_org_with_employee
+    from tests.legacy_tasks import legacy_task
+    from tests.test_workers import _make_org_with_employee, _owner_of
 
-    org_id, headers, project_id, employee_id = await _make_org_with_employee(
+    org_id, _headers, project_id, employee_id = await _make_org_with_employee(
         client, "errlog-worker@example.com"
     )
-    task_id = (
-        await client.post(
-            f"/api/organizations/{org_id}/tasks",
-            json={
-                "title": "کاری که شکست می‌خورد",
-                "project_id": project_id,
-                "assigned_employee_id": employee_id,
-            },
-            headers=headers,
-        )
-    ).json()["id"]
+    task_id = await legacy_task(
+        session_factory,
+        org_id,
+        await _owner_of(session_factory, org_id),
+        title="کاری که شکست می‌خورد",
+        project_id=project_id,
+        assigned_employee_id=employee_id,
+    )
 
     async def _boom(*args, **kwargs):
         raise RuntimeError("provider returned a malformed response")