ci(lint): declare getNodeFreshness as a readonly browser global

[dborup]

Problem

The "🧹 Frontend lint (eslint no-undef)" CI step (npx eslint public/*.js, eslint 8.57.1) fails on master e17377d8 with two errors:

public/live.js   3191:45  error  'getNodeFreshness' is not defined  no-undef
public/nodes.js   251:9   error  'getNodeFreshness' is not defined  no-undef
✖ 91 problems (2 errors, 89 warnings)

They were introduced with relay-aware node staleness (06cd0b73, 6edb1820, 2026-08-06) but stayed hidden because the CI job always stopped at an earlier step; the first run to reach lint was the CI integration draft #61.

Cause: missing lint declaration, not a runtime error

• public/roles.js:528 assigns window.getNodeFreshness = function (…) directly in the file's top-level IIFE (not in a callback), so it exists as soon as roles.js has executed. Loading roles.js alone in a VM confirms it is a function immediately after load.
• public/index.html loads roles.js synchronously first (line 177), before nodes.js (216) and live.js (224); none of them use defer/async/type="module", and index.html is the only page loading live.js/nodes.js.
• Both call sites are additionally guarded: window.getNodeFreshness ? getNodeFreshness(…) : null.

ESLint only reports it because the bare call getNodeFreshness(…) refers to a browser global that is not listed in .eslintrc.json, unlike the neighbouring getNodeStatus / getHealthThresholds helpers.

Change

.eslintrc.json only (+1): add "getNodeFreshness": "readonly" to globals, alphabetically between getHealthThresholds and getNodeStatus, following the file's existing convention. No change to no-undef or any other rule, workflows, or runtime code.

Verification (local, eslint 8.57.1 — the version the CI step installed — in an isolated scratch directory, workflow command eslint public/*.js)

• Baseline master: ✖ 91 problems (2 errors, 89 warnings) — identical to CI, including the two errors above.
• This branch: exit 0, ✖ 89 problems (0 errors, 89 warnings); the 89 warning lines are identical to baseline (pre-existing no-unused-vars warnings, not addressed here).
• Mutation in a scratch copy: renaming the live.js call to getNodeFreshnessTypo fails again with 'getNodeFreshnessTypo' is not defined (no-undef), so real undefined references are still caught.
• .eslintrc.json parses as JSON; git diff --check clean.

Relation to other PRs

Independent of #56, #59 and #60. It is being added to the CI integration draft #61 ("CI integration only — do not merge") so the combined run can get past the lint step. GitHub CI for this PR on its own will still stop earlier (the Kpa-clawbot#1648 M4 scan is fixed by #56) and may hit the known flaky ingestor watchdog test.

🤖 Generated with Claude Code