Can't Edit Files with Paths That Contain Brackets

Next.js has a file-based router, which uses brackets for dynamics routes: e.g. `app/issues/[id]/page.tsx`.

Workspace is having trouble dealing with that file path:

- Expected: Workspace edits the existing file.
- Actual: During the planning phase it recognizes the existing file, but during the update phase it creates a brand new file (at the same path).