fix: make plugin hooks run on Node 21+ and green the suite under modern Node (#2184)

ROOT CAUSE: hooks load plugin-hook-bootstrap.js via
`node -e "...; process.argv.splice(1,0,s); require(s)"`. On Node 21+,
require.main is `undefined` under --eval, so the `if (require.main === module)`
guard was false and main() never ran — every plugin hook silently no-op'd
(e.g. the MCP-health PreToolUse hook stopped blocking). CI (Node 18/20) hid
this; it only surfaces on Node 21+. Fix: also run main() when require.main is
undefined (the eval-bootstrap case), while staying dormant on real imports.

Also clears pre-existing main debt the full local suite enforces:
- catalog:sync — README/docs agent+skill counts drifted after recent merges
- tests/ci/supply-chain-watch-workflow: update checkout SHA to the merged v6.0.3 (#2183)
- markdownlint + check-unicode-safety --write across docs/skills

Suite: 2683/2683 green under Node v25; lint + unicode clean.

Co-authored-by: ECC Test <ecc@example.test>

AGENTS.md

@@ -1,6 +1,6 @@
 # Everything Claude Code (ECC) — Agent Instructions
 
-This is a **production-ready AI coding plugin** providing 63 specialized agents, 251 skills, 79 commands, and automated hook workflows for software development.
+This is a **production-ready AI coding plugin** providing 64 specialized agents, 255 skills, 79 commands, and automated hook workflows for software development.
 
 **Version:** 2.0.0-rc.1
 
@@ -149,8 +149,8 @@ Troubleshoot failures: check test isolation → verify mocks → fix implementat
 ## Project Structure
 
 ```
-agents/          — 63 specialized subagents
-skills/          — 251 workflow skills and domain knowledge
+agents/          — 64 specialized subagents
+skills/          — 255 workflow skills and domain knowledge
 commands/        — 79 slash commands
 hooks/           — Trigger-based automations
 rules/           — Always-follow guidelines (common + per-language)