The incremental sync used `find -type f` which misses symlinks (type l),
so dataset symlinks were never detected and synced to the sandbox.
Additionally, `tar.add()` without `dereference=True` would store broken
symlinks pointing to host-only paths.
- _list_local_changed_files: match both regular files and symlinks
- _tar_workspace_entries: dereference symlinks to pack actual content
- Unify dataset path to `datasets/` (plural) in prompts and SKILL.md
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
