Transform win-dev-skills into a true skills marketplace

[Jaylyn-Barbee]

Goal

Evolve microsoft/win-dev-skills from a WinUI-focused plugin into a true marketplace for anything Windows-related — additional skills and MCP servers (WinDbg, XAML tooling, diagnostics, packaging, interop, security, …) with curation and a clear contribution path.

Model this on dotnet/skills: a discoverable catalog, per-skill ownership, quality bar, and a documented "add your skill" flow.

Workstreams

• Marketplace infra & curation — grow marketplace.json from one plugin to a multi-plugin catalog (per-skill entry, category/tags, independent versioning), keep the .claude-plugin / .agents / .codex-plugin manifests in sync, make skills discoverable, and define the curation gate: quality bar to be listed, per-skill ownership, review/deprecation process, and the release-tag pinning story.
• Contribution path — CONTRIBUTING guide for new skills/MCP servers, skill template/scaffold, review checklist, ownership model.
• Seed skills (tracked as sub-issues below).

Seed skills

• [Skill] WinUI runtime error diagnostics #127
• [Skill] WinDbg — crash dump & Time Travel Debugging #128
• [Skill] ETW / .etl trace analysis #129

References

• Model: https://github.com/dotnet/skills