Add 828 skills from gh-skills migration

[dhruvchand]

Adds 828 skills from the nine repositories that account for roughly 81% of public gh-skills install volume, as preparation for migrating gh-skills onto AgentFinder.

What is added

repo	skills	gh-skills installs
github/awesome-copilot	411	67,335
microsoft/skills	161	7,327
k-dense-ai/scientific-agent-skills	158	5,976
mattpocock/skills	41	21,318
shader-slang/slang-skills	29	8,789
paulnsorensen/easy-cheese	18	16,669
cli/cli	5	3,239
smartcrabai/agent-skills	4	2,782
github/gh-stack	1	7,129

Catalog grows 1,104 to 1,932 entries.

Why these repos

gh-skills install demand is heavily concentrated, and the catalog previously served only about 3% of it. The two sets were built differently: the catalog is vendor-curated top-down, while gh-skills demand is community-driven bottom-up. github/awesome-copilot alone is 39% of public installs and had zero entries here.

These nine repos take coverage from 3% to roughly 81% of public installs. The remaining ~200 repos are worth 16,705 installs between them, so they are deliberately left out as long tail.

Descriptions

Taken from each SKILL.md's own YAML frontmatter rather than generated, so the copy matches what each publisher wrote. Where frontmatter had no description, the first prose paragraph is used. All are trimmed at sentence boundaries to the existing 152-character convention.

Deduplication

Three cases were handled rather than imported blindly:

• 31 skipped as already catalogued. microsoft/skills vendors microsoft/azure-skills under .github/plugins/ with identical blob SHAs, and those entries already exist (194 discovered, 161 added).
• 6 in-repo duplicates collapsed. Some repos mirror a skill under both .claude/skills/ and skills/, which would have produced two files sharing one URN. The canonical path is kept.
• 1 filename collision resolved. Publisher directories are flat, so github/awesome-copilot and github/gh-stack can clash; disambiguated with a repo prefix.

Validation

• All 828 files parse as JSON with every required field present
• identifier, metadata.sourceSet and publisher directory are mutually consistent
• url contains metadata.repoPath
• No duplicate identifiers anywhere in the catalog
• 10/10 sampled URLs return HTTP 200
• No existing catalog files modified, renamed or deleted

Notes for review

• paulnsorensen/easy-cheese (18 skills, 16,669 installs) is worth a human look. It is actively developed, but the skills are cheese-themed (melt, mold, cure, brie), so it may be a demo or joke set that would look odd ranked highly.
• shader-slang/slang-skills has 8,789 installs but only 1 star. It is a legitimate vendor repo for the Slang shading language; flagged because it would fail a stars-only quality bar.

[Copilot]

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