Rename capture-event skill to kb-capture-event

[williamthorsen]

Description

Rename the capture-event skill to kb-capture-event, bringing the event command family under the kb- knowledge-base toolchain namespace. Skills install into a single flat ~/.claude/skills/ directory shared with unrelated skills, so a generic verb-noun name risks collisions and scatters the KB toolchain across the alphabetical skill list. The prefix namespaces the family and groups it contiguously (kb-add, kb-capture-event, kb-curate, kb-edit, kb-retrieve, kb-retrieve-events, kb-update-events). The assertion-vs-event distinction moves into each skill's description rather than living in the name.

This is a breaking rename of a shipped, user-invocable skill: the invocation changes from /capture-event to /kb-capture-event.

Part of the per-type record architecture epic (#848). Companions kb-update-events (#850) and kb-retrieve-events (#851) are named under this convention from the start; only the already-shipped capture-event needs a rename.

Acceptance criteria

Must have

• The skill is kb-capture-event end to end: content directory, name: frontmatter, and bundled helper output (content/skills/kb-capture-event/kb-capture-event.mjs).
• The bundle-skill-helpers.ts target and the helper source directory are renamed to match.
• All cross-references to the old name are updated: kb README.md, _data/artifact-conventions.md, sibling SKILLs that mention it, invocation snippets, and the rovodev skill-discovery list.
• No references to capture-event remain (grep confirms zero outside changelog history).
• The existing test suite and the skill-bundle smoke test pass under the new name.