feat(engine): the manager — chat orders, team, triage, verdicts, bootstrap

Phase 3 of the AI-workforce engine (TODO-agent-2):

- engine/manager.py: ManagerTurns.chat (CREATE_TASK/PAUSE/RESUME/CANCEL,
  HIRE/UPDATE_EMPLOYEE/FIRE, KNOWLEDGE), triage (ASSIGN/REJECT/ASK_USER),
  final_review (COMPLETE/REVISE +cycle), error_review (RESOLVE_ERROR/CANCEL),
  bootstrap_team; post_user_message now delegates to it.
- One billing path: call_model/BillingScope in runner.py is the single model
  entry point (fixes the agybot chat-billing bug).
- Team changes capped at 3/turn, employee cap, last manager cannot be fired,
  hires pick a granted model of the requested tier strictly.
- container_engine.py wires the real WorkforceBootstrapPort.
- Fixes: REVISE is a body tag (prompt and parser now agree); ASSIGN
  employee="" means pick-for-me; the runner's protocol-error retry is capped by
  engine_max_protocol_retries (was unbounded until the turn timeout).
- 20 new manager tests + regression tests; report in
  docs/plan/reports/agent-2-phase-3.md.

apps/api/app/core/config.py

@@ -144,6 +144,10 @@ class Settings(BaseSettings):
 
     # >>> agent-2 (AI workforce engine): add settings ONLY between these markers
     engine_max_tool_calls_per_turn: int = 40
+    #: Consecutive malformed replies tolerated before a turn gives up. Without
+    #: it a model that repeats the same protocol mistake would be called until
+    #: the turn timeout, hundreds of paid calls later.
+    engine_max_protocol_retries: int = 3
     engine_turn_timeout_seconds: int = 900
     engine_max_cycles: int = 6
     engine_max_employees: int = 20