The seen-skills dedup was using a temp file written via SessionStart,
but PreToolUse hooks can't update CLAUDE_ENV_FILE. This caused errors
when the temp file became stale or inaccessible across session clears.
Now VERCEL_PLUGIN_SEEN_SKILLS is a comma-delimited string stored
directly in the session environment. SessionStart initializes it as
empty, and the PreToolUse hook reads/updates process.env in-place.
Extract glob-to-regex and seen-skills file utilities into hooks/patterns.mjs
for reuse across the PreToolUse hook and validation script. Add
validateSkillMap to skill-map-frontmatter.mjs. Expand plugin tags for
chat-sdk/bot variants. Comprehensive tests for all new modules.
John Lindquist