refactor(schedule): move orchestrator to application/ + review fixes (stage 8)

Follow-up to the layered refactor (review-driven):

- Move scheduling/orchestrator.py -> application/orchestrator.py
  (orchestrator is application-level coordination, not a cron-trigger
  primitive; matches the intended target tree)
- Migrate orchestrator re-exports from scheduling/__init__.py to
  application/__init__.py; scheduling/ now exposes only CronScheduler
- Rewrite imports + 5 mock.patch string targets in test_janitor.py and
  the orchestrator import in test_layering.py
- Update docstring refs in application/service.py + execution/worker.py
- Add 4 runner smoke tests (test_layering.py): _limited_log under-limit /
  empty-sentinel / above-MAX_LOG_BYTES truncation; execute_artifact
  rejects unsupported script_type with ValueError
- infrastructure/__init__.py re-exports SchedulerStorageClient so
  ``from schedule.infrastructure import SchedulerStorageClient`` is a
  stable top-level surface
- CLAUDE.md engineering note: extend the commit trail to 7476c27 and
  note the stage-8 orchestrator placement

Zero behavior change; schedule/pyproject.toml untouched. 29 tests green.

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

schedule/src/schedule/application/__init__.py

@@ -1,9 +1,20 @@
 """Application layer — service assembly for the scheduler.
 
-Home of the old flat ``schedule/service.py``: ``SchedulerService`` plus the
-``build_object_store`` / ``build_storage_http_client`` factories.
+Houses:
+
+- ``SchedulerService`` plus the ``build_object_store`` /
+  ``build_storage_http_client`` factories (the old flat ``schedule/service.py``).
+- ``DispatchOrchestrator`` and the cron / node event constants (the old
+  ``schedule/orchestrator.py`` — the outbox-polling / DAG coordinator is
+  application-level glue, not a cron-trigger primitive).
 """
 
+from schedule.application.orchestrator import (
+    NODE_EXECUTE_EVENT,
+    NODE_FINISHED_EVENT,
+    SCHEDULE_RUN_REQUESTED_EVENT,
+    DispatchOrchestrator,
+)
 from schedule.application.service import (
     SchedulerService,
     build_object_store,
@@ -14,4 +25,8 @@ __all__ = [
     "SchedulerService",
     "build_object_store",
     "build_storage_http_client",
+    "DispatchOrchestrator",
+    "SCHEDULE_RUN_REQUESTED_EVENT",
+    "NODE_EXECUTE_EVENT",
+    "NODE_FINISHED_EVENT",
 ]

schedule/src/schedule/application/service.py

@@ -3,7 +3,7 @@
 Composes three single-purpose components into one bootable service:
 
   - :class:`schedule.scheduling.scheduler.CronScheduler` — APScheduler + cron sync loop
-  - :class:`schedule.scheduling.orchestrator.DispatchOrchestrator` — Outbox polling + DAG
+  - :class:`schedule.application.orchestrator.DispatchOrchestrator` — Outbox polling + DAG
   - :class:`schedule.execution.worker.NodeExecutor` — node-level execution
 
 This module also exposes the factory function ``build_object_store``
@@ -36,7 +36,7 @@ from common.storage import create_storage
 from loguru import logger
 from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
 
-from schedule.scheduling.orchestrator import DispatchOrchestrator
+from schedule.application.orchestrator import DispatchOrchestrator
 from schedule.scheduling.scheduler import CronScheduler
 from schedule.execution.worker import NodeExecutor
 

schedule/src/schedule/execution/worker.py

@@ -1,6 +1,6 @@
 """Node-level worker: executes one ``job.node.execute`` event.
 
-The orchestrator (see ``schedule.scheduling.orchestrator``) writes a ``job.node.execute``
+The orchestrator (see ``schedule.application.orchestrator``) writes a ``job.node.execute``
 Outbox row with all the metadata needed to run the node (script type,
 artifact location, timeout, arguments ...). The polling loop picks those up
 and calls :meth:`NodeExecutor.handle_node_execute`. This module owns the

schedule/src/schedule/infrastructure/__init__.py

@@ -1 +1,5 @@
 """Infrastructure layer — external I/O adapters (storage API)."""
+
+from schedule.infrastructure.storage import SchedulerStorageClient
+
+__all__ = ["SchedulerStorageClient"]

schedule/src/schedule/scheduling/__init__.py

@@ -1,22 +1,11 @@
-"""Scheduling layer — cron trigger + DAG orchestration.
+"""Scheduling layer — cron trigger.
 
-Home of the old flat ``schedule/scheduler.py`` (``CronScheduler``) and
-``schedule/orchestrator.py`` (``DispatchOrchestrator``). Classes moved
-byte-identical in the layered refactor; names unchanged.
+Home of the old flat ``schedule/scheduler.py`` (``CronScheduler``).
+The class moved byte-identical in the layered refactor; name unchanged.
+The outbox-polling orchestrator used to live here too, but it is an
+application-level coordinator — see ``schedule.application.orchestrator``.
 """
 
-from schedule.scheduling.orchestrator import (
-    NODE_EXECUTE_EVENT,
-    NODE_FINISHED_EVENT,
-    SCHEDULE_RUN_REQUESTED_EVENT,
-    DispatchOrchestrator,
-)
 from schedule.scheduling.scheduler import CronScheduler
 
-__all__ = [
-    "CronScheduler",
-    "DispatchOrchestrator",
-    "SCHEDULE_RUN_REQUESTED_EVENT",
-    "NODE_EXECUTE_EVENT",
-    "NODE_FINISHED_EVENT",
-]
+__all__ = ["CronScheduler"]