Independent plugins for DeepSeek Harness

Key features

• skin.json is missing id / name / author / license, any one is rejected (author and license are required, respecting BSD-3 retention requirements)
• previewIt only takes effect during runtime and will be lost when refreshed. Do not write the applied key.
• a11y.css only allows dataurl() with relative paths, http / // / file: / ftp / ws is always rejected (preventing skin packages from making external requests).
• The total number of custom skins is ≤ 8.
• appliedWrite the applied key, and press the track to resume when the page is loaded.