feat(policy): add delegation and escalation contracts

tests/test_policy_contracts.py

@@ -10,6 +10,8 @@ from govoplan_core.core.configuration_safety import (
     ui_managed_configuration_fields_requiring_approval,
 )
 from govoplan_core.core.policy import (
+    FunctionAssignmentEscalationRule,
+    FunctionAssignmentGovernanceDecision,
     PolicyDecision,
     PolicySourceStep,
     parse_policy_source_path,
@@ -19,6 +21,34 @@ from govoplan_core.core.policy import (
 
 
 class PolicyContractTests(unittest.TestCase):
+    def test_function_assignment_policy_serializes_delegation_and_escalation(self) -> None:
+        decision = FunctionAssignmentGovernanceDecision(
+            allowed=True,
+            delegation_allowed=True,
+            maximum_delegation_depth=2,
+            maximum_delegated_validity_days=30,
+            escalation_rules=(
+                FunctionAssignmentEscalationRule(
+                    step="authority",
+                    target_function_id="function-escalation",
+                    timeout_hours=48,
+                ),
+            ),
+        )
+
+        payload = decision.to_dict()
+
+        self.assertEqual(2, payload["maximum_delegation_depth"])
+        self.assertEqual(30, payload["maximum_delegated_validity_days"])
+        self.assertEqual(
+            "function-escalation",
+            payload["escalation_rules"][0]["target_function_id"],
+        )
+        self.assertEqual(
+            "function-escalation",
+            decision.escalation_rule("authority").target_function_id,
+        )
+
     def test_policy_source_paths_are_stable_and_round_trip(self) -> None:
         self.assertEqual(policy_source_path("system"), "system")
         self.assertEqual(policy_source_path("tenant", "tenant-1"), "tenant:tenant-1")