QTZPOC-20

QTZPOC-20: Implement model import workflow for .sientia bundles

Introduces the import_model workflow and its associated activities to enable importing .sientia bundles into MLflow and MongoDB. This includes:

*   New core workflow and activity logic for handling bundle download, decryption, validation, MLflow provisioning (experiments, runs, registered versions), and MongoDB model document creation.
*   Comprehensive E2E and unit test suites, including a dedicated test harness and a manual run script for development.
*   Updated .env.example and README.md with new configurations and usage instructions.
*   Ensures correct MLflow model source resolution for legacy loader compatibility and robust MongoDB document management.
*   Refactors existing utility scripts into a scripts/ directory.

laborious/worker/worker.py

@@ -77,6 +77,19 @@ with workflow.unsafe.imports_passed_through():
 POD_ID = os.getenv('HOSTNAME')
 SDK_METRICS_PORT = int(os.getenv('HTTP_SDK_METRICS_PORT', '9091'))
 
+# The values that turn the import worker on. Anything else — unset, empty, `0`, `false`, a typo —
+# leaves the four default workers alone and polls no import queue at all.
+IMPORT_ENABLED_VALUES = ('1', 'true', 'yes', 'on')
+
+
+def import_worker_enabled() -> bool:
+    """Whether this runtime registers the fifth (import) worker.
+
+    Read at worker start, not per workflow: containment (QTZPOC-19) wants the importer in its own
+    runtime with its own credentials, and this flag is what makes that a deployment decision.
+    """
+    return os.getenv('IMPORT_MODEL_ENABLED', '').strip().lower() in IMPORT_ENABLED_VALUES
+
 
 async def main():
     """
@@ -250,7 +263,7 @@ async def main():
     # its own credentials, and a flag lets that be a deployment decision instead of forcing every
     # Laborious runtime to poll the import queue today. Unset, the four workers above are unaffected
     # and no import queue is polled at all.
-    if os.getenv('IMPORT_MODEL_ENABLED', '').strip().lower() in ('1', 'true', 'yes', 'on'):
+    if import_worker_enabled():
         logger.custom_info('Import model worker enabled', metadata_runtime)
         workers.append(
             prepare_worker(