Natural-language skill search returned a short, arbitrary list and never
surfaced NVIDIA (or OpenAI/Anthropic/HuggingFace) skills. Two causes:
1. The runtime index collapses every GitHub tap into source="github", so
there was no way to find or filter by provider at the CLI — the per-tap
identity only existed in the docs-site catalog.
2. HermesIndexSource.search matched only name/description/tags (not the
identifier or provider) and broke at the first `limit` hits in raw index
order, burying the most relevant skills. `search` also defaulted to
--limit 10 against an 86k-entry catalog.
Changes:
- GitHubSource stamps a per-tap provider label (extra.provider) on each
skill via github_provider_for(); source stays "github" so dedup/floor/
index-skip logic is untouched. Flows into the built index.
- HermesIndexSource.search now matches identifier + provider too, and
collect-then-ranks (exact > prefix > whole-word > substring) instead of
break-at-limit.
- --source nvidia|openai|anthropic|huggingface|voltagent|gstack|minimax
provider filters for browse/search (narrows merged results by provider).
- search --limit default 10 -> 25; table Source column shows the provider
label for github skills.
Tested: 181 unit tests pass; E2E against the live runtime index confirms
'nvidia'/'cuda' searches now surface NVIDIA-provider skills and
--source nvidia narrows to exactly the NVIDIA catalog.