Raise the TypeScript servers' Node floor to 24; engines, docs and CI disagree #5168

The four TypeScript servers declare "engines": {"node": ">=20"}, and their 2.0.0 CHANGELOG entries and READMEs say "Node.js 20 or later" (from #4856). Nothing else agrees with that:

• CI tests Node 22, 24 and 26 and never runs Node 20 (typescript.yml, from Test on Node 24 (and 26) alongside 22 #5068).
• AGENTS.md, docs/quality-gate.md and the local-dev skill name Node 22 as the oldest supported version.
• Node 20 reached end of life in April 2026, and Node 22 reaches end of life in April 2027.
• The test suite already needs Node 22.12 or later (require() of ESM in server-version.test.ts).

The v2.0.0 release ledger found this mismatch.

Change

Raise the floor to Node 24 before 2.0.0 publishes:

• engines.node becomes >=24 in the four package.json files and in package-lock.json.
• The README "Requirements" lines and the 2.0.0 CHANGELOG entries say "Node.js 24 or later". 2.0.0 is not on npm yet, so the entry is corrected in place. There is no new changeset, and the version stays 2.0.0.
• The CI matrix becomes 24 and 26. Every workflow's node-version: 22 becomes 24.
• AGENTS.md, docs/quality-gate.md and the local-dev skill name 24 as both the development version and the oldest supported version.