fix(company): stop/resume identity truth, failure-path closure, quota park

OBS-11 — stop/resume killed pure-native runs over a phantom external pin.
Role templates' preferred_external_agent leaked into execution identity even
when the user requested native and execution actually ran native; on resume
the availability gate trusted the pin and failed every non-terminal item.
Root fixes across the whole chain:
- Staffing card per-role defaults are now the RESOLVED backend (explicit
  session agent choice > runnable template preference > native), never a
  hardcoded external default; seat enrichment and the dispatch selector's
  locked branch downgrade provably unavailable externals to native and
  record the wish in execution_agent_unavailable.
- The resume availability gate fails closed only when a resumable external
  session actually exists; a bare pin heals to native (snapshot AND task
  durable identity) and the run resumes — mirroring dispatch fallback.
- Suspend-checkpoint replies: force_resume (chat/headless spelling) is
  recognized alongside ui_force_resume, and bare continuation tokens
  (English and Chinese spellings) take the plain-resume path instead of
  being routed to the final decider as content, which reopened the
  already-approved intake card.

OBS-5 — failed runs never closed and dropped new input. The dispatcher's
convergence exit now settles terminally-failed runs (status=failed,
lifecycle=closed_failed, run_failure metadata) and emits a
company_run_failure_review card whose replies never swallow messages:
dismiss acknowledges, content falls through so normal routing starts a
fresh run. _maybe_resume_existing_company_runtime no longer re-executes a
terminally-failed tree: control replies get an honest closed status,
content-bearing input starts a new run.

OBS-6 — provider quota exhaustion terminally failed work items. Rate-limit
rejections are classified (LLMProvider.is_rate_limit_error, covering
status codes, exception types, and English/Chinese provider error text),
the agent runtime raises typed ProviderQuotaExhaustedError instead of
burning conversation-feedback retries, and the company dispatcher parks:
the item returns to READY (attempt interrupted, no terminal failure), the
member session idles, and claiming backs off exponentially (60s doubling
to a 900s cap; a quiet 30min resets the streak) before resuming
automatically.

Verified end-to-end on the real minimax-m3 campaign: same goal, same 300s
stop point, same run shape that previously killed the whole tree within
90s now resumes cleanly and completes with all items approved; staffing
defaults native for all 11 roles.

Tests: test_stop_resume_native_pin (10), test_run_failure_settlement (6),
test_provider_quota_park (9); attempt-ledger, recruiter, and
suspend-resume suites updated to the new contracts (their old assertions
pinned the defective behaviors).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_company_runtime_suspend_resume.py

@@ -1146,8 +1146,12 @@ class CompanyRuntimeSuspendResumeTests(unittest.IsolatedAsyncioTestCase):
 
         engine.company_executor = DummyCompanyExecutor()
 
+        # A bare "continue" is a control reply and takes the plain-resume
+        # path (OBS-11); only content-bearing text routes to the final
+        # decider as a follow-up.
+        followup_text = "Additional requirement: add a risk-analysis section to the report"
         response = await engine._maybe_resume_checkpoint(
-            "continue",
+            followup_text,
             "sess-parent",
         )
         checkpoints = await store.get_pending_checkpoints(
@@ -1161,18 +1165,18 @@ class CompanyRuntimeSuspendResumeTests(unittest.IsolatedAsyncioTestCase):
         self.assertEqual(response, "ceo handled follow-up")
         self.assertEqual(captured["plan"].metadata["final_decider_role_id"], "executor")
         self.assertEqual(routed_task.status, TaskStatus.PENDING)
-        self.assertEqual(routed_task.context_snapshot["user_supplied_input"], "continue")
-        self.assertEqual(routed_task.metadata["latest_user_directive"], "continue")
-        self.assertEqual(routed_task.metadata["manager_mutation_user_input"], "continue")
+        self.assertEqual(routed_task.context_snapshot["user_supplied_input"], followup_text)
+        self.assertEqual(routed_task.metadata["latest_user_directive"], followup_text)
+        self.assertEqual(routed_task.metadata["manager_mutation_user_input"], followup_text)
         self.assertTrue(routed_task.metadata["followup_routed_to_final_decider"])
         self.assertEqual(checkpoints, [])
         assert refreshed_item is not None
         self.assertEqual(refreshed_item.phase, Phase.READY)
         self.assertEqual(refreshed_item.metadata.get("dispatch_hold"), "")
         self.assertEqual(refreshed_item.metadata.get("resume_source"), "primary_session_followup")
-        self.assertEqual(refreshed_item.metadata.get("resume_user_reply"), "continue")
-        self.assertEqual(refreshed_item.metadata.get("latest_user_directive"), "continue")
-        self.assertEqual(refreshed_item.metadata.get("manager_mutation_user_input"), "continue")
+        self.assertEqual(refreshed_item.metadata.get("resume_user_reply"), followup_text)
+        self.assertEqual(refreshed_item.metadata.get("latest_user_directive"), followup_text)
+        self.assertEqual(refreshed_item.metadata.get("manager_mutation_user_input"), followup_text)
         self.assertEqual(refreshed_item.metadata.get("current_turn_mode"), "dispatch_required")
         self.assertTrue(refreshed_item.metadata.get("followup_routed_to_final_decider"))