Fix UI freezes with large workspaces (#536)

crates/common/yaak-database/src/update_source.rs

@@ -21,5 +21,9 @@ impl UpdateSource {
 #[serde(rename_all = "snake_case", tag = "type")]
 pub enum ModelChangeEvent {
     Upsert { created: bool },
+    /// A delete for a workspace implies deletion of every model in that
+    /// workspace — children are bulk-deleted without their own change rows or
+    /// events, and consumers must prune the subtree themselves (the frontend
+    /// model store does this centrally).
     Delete,
 }