chore: align acpx tooling with openclaw stack

[dutifulbob]

Summary

This PR completes the ACPX tooling alignment with OpenClaw conventions.

1) Node baseline + rule parity

• raised runtime baseline to Node >=22.12.0
• re-enabled unicorn/no-array-sort by removing the temporary exception
• updated usage to toSorted() where needed

2) Single check pipeline in CI

• added canonical check script:
  • pnpm run format:check && pnpm run typecheck && pnpm run lint && pnpm run build && pnpm run test
• CI now runs pnpm run check

3) pnpm cutover

• switched package management to pnpm
• added packageManager: pnpm@10.23.0
• replaced package-lock.json with pnpm-lock.yaml
• updated scripts/workflows/hooks from npm-centric commands to pnpm

4) Docs/static checks

• added docs format + lint scripts:
  • format:docs, format:docs:check, lint:docs, check:docs
• CI now also runs pnpm run check:docs
• added .markdownlint-cli2.jsonc to keep docs lint useful without forcing a massive legacy docs rewrite

5) tsgo in checks

• added @typescript/native-preview
• changed typecheck to tsgo --noEmit
• kept typecheck:tsc as an explicit fallback script

Build migration (already included in this PR)

• migrated bundling from tsup to tsdown
• build command:
  • tsdown src/cli.ts --format esm --dts --clean --platform node --target node22 --no-fixedExtension
• preserves artifact contract:
  • dist/cli.js
  • dist/cli.d.ts

Validation

• pnpm run check ✅
• pnpm run check:docs ✅