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_integration_thread_project.py

@@ -16,6 +16,7 @@ from app.application.container_engine import build_scheduler
 from app.infrastructure.db.models import AiModelRow, OrganizationRow
 from app.infrastructure.repositories.engine import PipelineStateRepository
 from app.infrastructure.repositories.workforce import TaskRepository
+from tests.billing_helpers import fund_org
 from tests.conftest import auth_header
 from tests.engine_fakes import ScriptedModel, ScriptedReply
 from tests.test_org_wizard import _complete, _manager
@@ -58,6 +59,9 @@ async def test_an_order_in_a_thread_without_a_project_gets_the_orgs_project(
     org_id = body["organization"]["id"]
     project_id = body["project"]["id"]
 
+    # prepaid (D-B): the wizard's org starts at zero credit, and an order costs model calls.
+    await fund_org(session_factory, org_id)
+
     # The web UI's way: a thread with no project_id.
     created = await client.post(
         f"/api/organizations/{org_id}/threads", json={"title": "گفتگو"}, headers=headers
@@ -66,8 +70,10 @@ async def test_an_order_in_a_thread_without_a_project_gets_the_orgs_project(
     assert created.json()["project_id"] is None
     thread_id = created.json()["id"]
 
-    # The order goes to the engine's manager. The HTTP message route builds its manager
-    # without pipeline states (workforce_service._manager_turns), so it cannot show the state.
+    # The order goes to the engine's manager. The HTTP message route builds its manager with
+    # the pipeline states too (workforce_service._manager_turns, covered by
+    # test_integration_order_route.py); this test calls the manager directly only to read the
+    # reply and the states in the same session.
     async with session_factory() as session:
         owner_user_id = (await session.get(OrganizationRow, org_id)).owner_user_id
         _, assistant = await build_scheduler(session).manager.chat(