chore: bump action runtime to Node 24

[aeaa1998]

Stack 1/3 — merge first.

• 1/3 this PR — Node 24 runtime → main
• 2/3 npm audit fixes → this branch
• 3/3 GitHub Actions bumps → 2/3

What

Moves the action off the node16 runtime.

File	Change
action.yml	using: node16 → node24
.github/workflows/check-dist.yml	setup-node 16.x → 24.x
.github/workflows/test.yml	build job had no setup-node at all — added one pinned to 24.x so it stops inheriting the runner default
package.json	@types/node ^22 → ^24, added engines: { node: ">=24" }
tsconfig.base.json	target/lib ES2022 → ES2024
README.md	Requirements note + dev-setup Node version

dist/ is unchanged — the ES2024 target produces identical output for this code, so there is no bundle churn to review here.

Why now

This is already happening to us implicitly. The runner log on this branch says:

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@08eba0b2…

Consumer impact

node16 → node24 is visible to consumers: self-hosted runners need runner v2.327.1 or later. GitHub-hosted runners are fine. Documented in the README.

Because of that, this release should be a minor bump (v1.1.0), not a patch. Note the repo has no floating v1 tag — consumers pin exact versions — so nobody is upgraded without opting in.

Validation

Dispatched CI on this branch, all green:

• build-test — the test job ran the action via uses: ./, confirming node24 resolves and runs on a real runner
• Check dist/

Also npm run all locally on Node 24.20.0: build, prettier, eslint, ncc, 15/15 tests.

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[weiyin]

nit: I feel like the engines requirement should be set to whatever version the code requires, not what version the github action runs on. We should set something here, but I feel like it's probably less than 24. Fine to roll with this though.

[aeaa1998]

@weiyin Good catch, you're right. Fixed in c57e469 — dropped to the actual toolchain floor, ^18.18.0 || ^20.9.0 || >=21.1.0 (eslint 9 / typescript-eslint 8, the strictest things in here). Nothing needs 24.

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