ci(plugin-ci): default to the Node plugins actually run on (20 → 24)

[ken-jo]

What

plugin-ci.yml node-version default: '20' → '24'. One line, plus the comment recording why the number is what it is.

No plugin repo overrides this input, so this moves all 7 at once — which is exactly why it was proven on one repo first.

Why '20' was wrong on two independent axes

It is end-of-life. Per nodejs/Release/schedule.json, v20 maintenance ended 2026-04-30. Four months of plugin CI has run on an unsupported runtime.

It was never the right number. The host spawns out-of-process plugins as process.execPath — the Electron binary — under ELECTRON_RUN_AS_NODE=1 (lvis-app/src/plugins/isolation/out-of-process-plugin.ts). A plugin's Node is Electron's bundled Node. Measured on the host's Electron 43 rather than read off a table:

$ ELECTRON_RUN_AS_NODE=1 electron -e 'console.log("electron="+process.versions.electron,"node="+process.versions.node)'
electron=43.0.0 node=24.17.0

So CI was testing four majors below production. A green suite on 20 could not answer whether the plugin works where it runs.

This already cost real work

lvis-plugin-ep Dependabot #194 (jsdom 29 → 30) fails CI with TypeError: webidl.util.markAsUncloneable is not a function. jsdom 30 → undici 8 → worker_threads.markAsUncloneable, added in Node 22. Production has it. Only CI did not — the bump passed locally on Node 26 the whole time. A dependency was blocked by the test environment rather than by the code, and the red check was describing a runtime no user has.

Proof before the flip

lvis-project/lvis-plugin-ep#226 pinned node-version: '24' for one repo and changed nothing else, so its result is evidence about the Node and not about anything bundled with it:

• ci / build-test pass, 41s, same self-hosted runner
• Log confirms the version was applied, not silently ignored: Acquiring 24.19.0 - arm64 … → node: v24.19.0

That last check matters: a with: block that gets ignored produces a green run too. The number had to be read back out of the run.

After this merges

1. Dispatch CI on each plugin repo's main and confirm all 7 are green on Node 24.
2. Close ep#226 — once the default is '24' the override merely restates it, and an override that restates the default is how a stale pin outlives its reason.
3. Unblock ep#194 (jsdom 30).

Maintenance

The comment ties the number to the host's Electron, not to "latest LTS". When lvis-app moves Electron majors, re-read Electron's bundled Node and move this with it.

[ken-jo]

Correction to the PR body: this moves 6 repos, not 7.

lvis-plugin-sdk does not call plugin-ci.yml at all — it is public, so it runs its own test.yml on GitHub-hosted runners and never touches the self-hosted group. The six that do inherit this default are meeting, ms-graph, ep, work-assistant, local-indexer, and template (verified by grepping each repo's ci.yml for plugin-ci.yml@main: 1 hit each, 0 for the SDK).

Worth recording how the wrong number got in: my first sweep queried .github/workflows/ci.yml in each repo and printed the node-version hits. For the SDK that request 404'd — no such file — and the empty result rendered identically to "exists, no override." A missing measurement read as a clean one. The SDK's Node version is a separate question with a separate answer, and this PR does not touch it.