feat: harden multi-host runtime coordination

tests/test_runtime_agents.py

@@ -123,3 +123,20 @@ def test_worker_disables_consumers_without_reclaiming_stale_identity(
             celery_app._worker_consumer,
             celery_app._worker_draining,
         ) = original_state
+
+
+def test_worker_child_replaces_inherited_database_pool(monkeypatch) -> None:
+    from govoplan_core import celery_app
+
+    calls: list[tuple[str, bool]] = []
+    monkeypatch.setattr(
+        celery_app,
+        "configure_database",
+        lambda url, *, dispose_previous=False: calls.append(
+            (url, dispose_previous)
+        ),
+    )
+
+    celery_app._reset_worker_process_database()
+
+    assert calls == [(celery_app.settings.database_url, True)]

tests/test_runtime_coordination.py

@@ -18,6 +18,7 @@ from govoplan_core.core.runtime_coordination import (
     list_runtime_nodes,
     register_runtime_node,
     request_runtime_node_drain,
+    runtime_composition_hash,
 )
 from govoplan_core.db.base import Base
 
@@ -128,3 +129,9 @@ def test_expired_lease_reassignment_increments_fence() -> None:
     finally:
         session.close()
         engine.dispose()
+
+
+def test_runtime_composition_hash_is_order_and_duplicate_independent() -> None:
+    assert runtime_composition_hash(("files", "core", "files")) == (
+        runtime_composition_hash(("core", "files"))
+    )