test+refactor: audit-row assertions + uniform PATCH rollback (review follow-ups)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/db/tests/fields.rs

@@ -1,7 +1,7 @@
-use db::{Db, DeleteOutcome, catalog, fields, vocab};
+use db::{Db, DeleteOutcome, audit, catalog, fields, vocab};
 use domain::{
-    AuditActor, AuthorityKind, FieldType, LocalizedLabel, NewFieldDefinition, ObjectInput,
-    Visibility,
+    AuditAction, AuditActor, AuthorityKind, FieldType, LocalizedLabel, NewFieldDefinition,
+    ObjectInput, Visibility,
 };
 use sqlx::PgPool;
 
@@ -257,6 +257,13 @@ async fn delete_field_definition_blocks_when_objects_use_it(pool: PgPool) {
     .await
     .unwrap();
 
+    let field_def_id = fields::field_definition_by_key(&mut *tx, "weight")
+        .await
+        .unwrap()
+        .unwrap()
+        .id
+        .to_uuid();
+
     let obj = catalog::create_object(&mut tx, AuditActor::System, &sample_object_input())
         .await
         .unwrap();
@@ -285,6 +292,14 @@ async fn delete_field_definition_blocks_when_objects_use_it(pool: PgPool) {
         DeleteOutcome::Deleted
     );
 
+    let history = audit::history_for(&mut *tx, "field_definition", field_def_id)
+        .await
+        .unwrap();
+    assert!(
+        history.iter().any(|e| e.action == AuditAction::Deleted),
+        "expected a Deleted audit entry for the field_definition"
+    );
+
     assert_eq!(
         fields::delete_field_definition(&mut tx, AuditActor::System, "weight")
             .await