feat(v2): enqueue and lease durable executions

tests/integration/test_sources_jobs.py

@@ -84,6 +84,16 @@ async def test_local_source_probe_archive_and_repository_targeted_job(
         )
         assert job.status_code == 201
         assert "destination_path" not in job.json()
+        execution = await client.post(
+            f"/api/v2/jobs/{job.json()['id']}/executions", headers=headers
+        )
+        assert execution.status_code == 202
+        assert execution.json()["state"] == "queued"
+        duplicate = await client.post(
+            f"/api/v2/jobs/{job.json()['id']}/executions", headers=headers
+        )
+        assert duplicate.status_code == 409
+        assert duplicate.json()["code"] == "execution_active"
         archived = await client.delete(f"/api/v2/sources/{source_id}", headers=headers)
         assert archived.status_code == 204
         assert (

tests/unit/test_execution_lifecycle.py

@@ -1,6 +1,11 @@
 from __future__ import annotations
 
-from backup_tool.execution import ACTIVE_STATES, TERMINAL_STATES, TransitionError, transition
+from backup_tool.execution import (
+    ACTIVE_STATES,
+    TERMINAL_STATES,
+    TransitionError,
+    transition,
+)
 
 
 def test_transitions_are_monotonic_and_terminal_states_cannot_change() -> None: