Implement 10 unit tests covering:
- Name validation (valid and invalid patterns)
- Save, load, and delete operations
- Multiple entries and overwrites
- Empty buckets and non-existent entries
- Invalid bucket names
- Persistence across reloads
Tests use unittest (stdlib) and mock folder_paths dependency,
ensuring the store logic is reliable without ComfyUI runtime.
Co-authored-by: Cursor Agent <cursoragent@cursor.com>
