## What changed
- Use `ExecutorFileSystem::read_file_stream` for capability files and executor skill resources regardless of whether filesystem sandboxing is active.
- Enforce per-file and bundle size limits incrementally as chunks arrive.
- Preserve the existing error for Windows resources when the required filesystem sandbox is unavailable.
GitOrigin-RevId: 1a40602a8f913588ec9a6ad7edd2d62eb82436e1