build: require Node >= 22 and build with Node 24

[antobinary]

What

Moves this plugin onto Node 24 and declares a supported-Node floor.

• package.json gains an engines field: "node": ">=22", mirrored into
  package-lock.json so the two agree.
• @types/node bumped to ^24.13.3 so the typings match the runtime the plugin
  is actually built with. It was declared twice, at ^20.3.1 and ^20.4.4;
  both are aligned here.
• CI moved from Node 20 to Node 24:
  • ts-code-compilation.yml — node-version: 20.x -> 24.x
  • ts-code-validation.yml — node-version: 20.x -> 24.x
  • publish-tag.yml — node-version: '20' -> '24'
  • build-plugin-deb-package.yml — NodeSource setup_20.x -> setup_24.x
• Debian packaging: debian/control Build-Depends raised from
  nodejs (>= 18) to nodejs (>= 22).

One new lockfile entry

undici-types appears as a new entry. It is a genuine dependency of
@types/node 24 (the 20.x line did not have it), not incidental churn. It is
the only package added anywhere in this change.

Why the Debian floor is 22 while the build pin is 24

Build-Depends is a minimum constraint, not a pin, so it is kept in step with
the engines floor — the package stays buildable on a Node 22 builder. The
version actually used to build is pinned separately, and that is 24 via the
NodeSource line in the workflow.

Testing

Against Node 24.20.0 / npm 11.19.0, running the same chain CI does:

• npm ci — PASS
• npx tsc — PASS
• npm run lint — PASS
• npm run build-bundle — PASS

Worth flagging for the future: TypeScript resolves to 5.2.2 here, the lowest of
any plugin in the set. @types/node 24 needs 5.2 or newer for Symbol.dispose
and Disposable, so this repo passes with no margin at all. A sibling repo
pinned at 5.1.3 failed tsc outright with ~55 errors inside @types/node's own
declaration files and had to have TypeScript moved forward. Nothing to do here
today — the ^5.1.6 spec already allows newer — but this is the repo most
likely to be tripped by the next typings bump.

Notes for review

Aside from undici-types, the lock diff is confined to the engines block and
the @types/node resolution. lockfileVersion is unchanged.