FRE-600: Fix code review blockers

- Consolidated duplicate UndoManagers to single instance
- Fixed connection promise to only resolve on 'connected' status
- Fixed WebSocketProvider import (WebsocketProvider)
- Added proper doc.destroy() cleanup
- Renamed isPresenceInitialized property to avoid conflict

Co-Authored-By: Paperclip <noreply@paperclip.ing>

node_modules/yaml/dist/parse/cst-stringify.d.ts

@@ -0,0 +1,8 @@
+import type { CollectionItem, Token } from './cst';
+/**
+ * Stringify a CST document, token, or collection item
+ *
+ * Fair warning: This applies no validation whatsoever, and
+ * simply concatenates the sources in their logical order.
+ */
+export declare const stringify: (cst: Token | CollectionItem) => string;