feat: convert all skills to dual-publish pattern
Add Claude plugin structure (.claude-plugin/plugin.json) and auto-discovery
(skills/<name>.md) to 15 skills. orch was already converted.
Skills converted:
- ai-tools-doctor, bd-issue-tracking, code-review, doc-review
- niri-window-capture, ops-review, playwright-visit, screenshot-latest
- spec-review, tufte-press, update-opencode, update-spec-kit
- web-research, web-search, worklog
Marketplace now lists all 16 skills for /plugin install.
Closes: skills-1ks
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>