fix(db): publish gate fires only on transition into public, not re-set

Preserves the documented set-to-current idempotent no-op: re-setting an
already-public object's visibility no longer rejects when a required field
was introduced after publish. Adds a regression test.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/db/src/catalog.rs

@@ -370,10 +370,11 @@ pub async fn set_visibility(
 
     let new_visibility = object.visibility.transition_to(target)?;
 
-    // The publish gate: a record may only become public once every required field
+    // The publish gate: a record may only *become* public once every required field
     // has a value. The typed inventory-minimum columns are already NOT NULL, so only
-    // the flexible required fields need checking here.
+    // the flexible required fields need checking here. Gated on an actual transition
-    if new_visibility == Visibility::Public {
+    // into public so a set-to-current no-op stays a no-op (never a late rejection).
+    if new_visibility == Visibility::Public && object.visibility != Visibility::Public {
         let missing = missing_required_fields(&mut *conn, &object.fields).await?;
 
         if !missing.is_empty() {

crates/db/tests/visibility.rs

@@ -256,3 +256,50 @@ async fn publishing_requires_all_required_fields_present(pool: PgPool) {
     let published = catalog::object_by_id(db.pool(), id).await.unwrap().unwrap();
     assert_eq!(published.visibility, Visibility::Public);
 }
+
+#[sqlx::test]
+async fn republishing_a_public_object_is_a_noop_even_with_a_new_required_field(pool: PgPool) {
+    use db::fields;
+    use domain::{FieldType, LocalizedLabel, NewFieldDefinition};
+
+    let db = Db::from_pool(pool);
+
+    let mut tx = db.pool().begin().await.unwrap();
+
+    // an already-public object (created public directly at the db layer)
+    let id = catalog::create_object(
+        &mut tx,
+        AuditActor::System,
+        &object("LM-2", Visibility::Public),
+    )
+    .await
+    .unwrap();
+
+    // a required field is introduced AFTER the object is already public
+    fields::create_field_definition(
+        &mut tx,
+        &NewFieldDefinition {
+            key: "inscription".into(),
+            field_type: FieldType::Text,
+            required: true,
+            group_key: None,
+            labels: vec![LocalizedLabel {
+                lang: "en".into(),
+                label: "Inscription".into(),
+            }],
+        },
+    )
+    .await
+    .unwrap();
+
+    // setting visibility to its current value stays an idempotent no-op — the publish
+    // gate only fires on an actual transition into public, not on a re-set.
+    catalog::set_visibility(&mut tx, AuditActor::System, id, Visibility::Public)
+        .await
+        .unwrap();
+
+    tx.commit().await.unwrap();
+
+    let obj = catalog::object_by_id(db.pool(), id).await.unwrap().unwrap();
+    assert_eq!(obj.visibility, Visibility::Public);
+}