Monaco SDK cancellation patch

The workbench pins Monaco Editor 0.57.0. Its upstream MIT-licensed esm/vs/base/browser/ui/tree/abstractTree.js schedules active-node changes with Delayer.trigger() but does not consume the returned promise. Closing references while this update is pending cancels the delayer and rejects that promise.

apps/workbench/scripts/prepare-monaco.mjs adds a catch to that one call using Monaco’s own onUnexpectedError. Monaco ignores its cancellation errors there; other errors still reach its normal unexpected-error handler. Circle does not filter renderer errors by message or hide other rejected promises.

The script checks the exact package version and complete input/output SHA-256 fingerprints. An already patched copy is accepted; any other SDK version or file content stops preparation for review. The script runs after dependency install, before development and builds, and before the component/editor test commands. Both development prebundling and packaged renderer bundling therefore read the same patched installed source. No generated SDK files are committed. Its existing copyright and MIT license remain intact.