fix(test): add root_plan_id to raw SQL in plan_phase_migration constraint tests

The step_try_insert_plan_with_phase_and_state function was using raw SQL to
insert a plan with an invalid phase value to test the CHECK constraint. However,
the raw SQL was missing the root_plan_id column, which is NOT NULL in the schema.
This caused the insert to fail with a NOT NULL violation instead of the intended
CHECK constraint violation on the phase column.

This fix adds root_plan_id to the raw SQL INSERT statement, setting it to the
same value as plan_id (for a root plan). This allows the test to properly
exercise the CHECK constraint on the phase column, ensuring the test fails for
the correct reason.

ISSUES CLOSED: #9411

features/steps/plan_phase_migration_steps.py

@@ -113,7 +113,11 @@ def step_insert_plan_with_phase_and_state(context: Any, phase: str, state: str)
 def step_try_insert_plan_with_phase_and_state(
     context: Any, phase: str, state: str
 ) -> None:
-    """Try to insert a plan with the specified phase and state, expecting failure."""
+    """Try inserting a plan without ORM defaults to exercise the phase constraint.
+
+    The direct SQL insert must provide both plan_id and root_plan_id so the
+    phase constraint is validated instead of failing on missing root_plan_id.
+    """
     session: Session = context.phase_rebaseline_session
     ulid = _next_ulid()
     now = _now_iso()
@@ -121,14 +125,15 @@ def step_try_insert_plan_with_phase_and_state(
         session.execute(
             text(
                 "INSERT INTO v3_plans "
-                "(plan_id, action_name, namespaced_name, namespace, "
+                "(plan_id, root_plan_id, action_name, namespaced_name, namespace, "
                 "phase, processing_state, description, tags_json, "
                 "created_at, updated_at) "
-                "VALUES (:pid, :aname, :nname, :ns, :phase, :state, "
+                "VALUES (:pid, :rpid, :aname, :nname, :ns, :phase, :state, "
                 ":desc, :tags, :cat, :uat)"
             ),
             {
                 "pid": ulid,
+                "rpid": ulid,
                 "aname": "local/phase-test-action",
                 "nname": "local/try-plan",
                 "ns": "local",