fix(test): resolve AmbiguousStep collision, invalid ULIDs, and edge commit

Three issues prevented the behave suite from running:

1. plan_persistence_steps.py and plan_repository_steps.py both defined
   @then('the retrieved plan description should be "..."'), causing an
   AmbiguousStep error that broke all ~50 feature files. Renamed the
   persistence step to "the persisted plan description should be".

2. The three-level hierarchy scenario used plan IDs containing O, I,
   and L which are excluded from the ULID charset. Replaced with valid
   characters (O->0, I->0, L->K).

3. resource_repository_steps.py flushed but never committed the edge
   row, so the delete method's separate session could not see it.

features/plan_persistence.feature

@@ -12,7 +12,7 @@ Feature: Plan persistence via LifecyclePlanRepository
     Given a new lifecycle plan with ID "01HV000000000000000000PP01"
     When I persist the plan via the plan repository
     Then I can retrieve the plan by ID "01HV000000000000000000PP01"
-    And the retrieved plan description should be "Persistence test plan"
+    And the persisted plan description should be "Persistence test plan"
 
   Scenario: Create a plan preserves all identity fields
     Given a new lifecycle plan with parent tree ID "01HV000000000000000000PP02" parent "01HV000000000000000000PP01" root "01HV000000000000000000PP01"
@@ -92,12 +92,12 @@ Feature: Plan persistence via LifecyclePlanRepository
     And the child plan should reference root "01HV0000000000000000TREE01"
 
   Scenario: Plan tree preserves three-level hierarchy
-    Given a root plan with ID "01HV0000000000000000ROOT01"
-    And a mid plan with ID "01HV0000000000000000MID001" under root "01HV0000000000000000ROOT01"
-    And a leaf plan with ID "01HV0000000000000000LEAF01" under parent "01HV0000000000000000MID001" and root "01HV0000000000000000ROOT01"
-    When I retrieve the leaf plan "01HV0000000000000000LEAF01"
-    Then the leaf plan parent should be "01HV0000000000000000MID001"
-    And the leaf plan root should be "01HV0000000000000000ROOT01"
+    Given a root plan with ID "01HV0000000000000000R00T01"
+    And a mid plan with ID "01HV0000000000000000M0D001" under root "01HV0000000000000000R00T01"
+    And a leaf plan with ID "01HV0000000000000000KEAF01" under parent "01HV0000000000000000M0D001" and root "01HV0000000000000000R00T01"
+    When I retrieve the leaf plan "01HV0000000000000000KEAF01"
+    Then the leaf plan parent should be "01HV0000000000000000M0D001"
+    And the leaf plan root should be "01HV0000000000000000R00T01"
 
   # Cross-restart scenarios
   Scenario: Plan status persists across database reconnection

features/steps/plan_persistence_steps.py

@@ -205,7 +205,7 @@ def step_retrieve_plan_by_id(context: Context, plan_id: str) -> None:
     context._pp_retrieved = plan
 
 
-@then('the retrieved plan description should be "{description}"')
+@then('the persisted plan description should be "{description}"')
 def step_plan_description(context: Context, description: str) -> None:
     """Verify the plan's description."""
     assert context._pp_retrieved.description == description

features/steps/resource_repository_steps.py

@@ -652,6 +652,7 @@ def step_parent_child_linked(context: Context, type_name: str) -> None:
     )
     session.add(edge)
     session.flush()
+    session.commit()
 
 
 @when("the parent resource is deleted")