chore!: require Node.js 22 or later

[MLawlz]

Summary

Raises the minimum Node.js version from 18 to 22 and bumps the SDK to 5.0.0. Node.js 18 reached end of life in April 2025 and Node.js 20 in April 2026, so 22 is the oldest release line still getting security fixes. There are no SDK code changes; this release only changes which Node versions are supported and tested.

Changes

• package.json: engines.node >=18 → >=22, version 4.41.4 → 5.0.0
• CHANGELOG.md: [5.0.0] entry, marked Breaking
• test.yml: matrix 18, 20 → 22, 24
• publish.yml, api-reference.yml, version-bump.yml: Node 20 → 24. This is required for the first two: pnpm refuses to install a project whose own engines doesn't match the running Node, so releases would fail on 20.
• docs/compat.md, CLAUDE.md: now say 22+; compat.md points Node 18/20 users to v4
• src/utils/live.ts: a comment no longer says Node 18 "is still supported"
• tests/unit/utils.test.ts: three user-agent assertions, explained below

Why the user-agent tests changed

They would have failed on the new matrix. Node 21 added a global navigator.userAgent ("Node.js/22"). buildUserAgent uses it as the User-Agent prefix and deliberately skips runtime_env=Node/<version> when that string already names Node. CI only ever ran 18 and 20, so the tests expected runtime_env. They now assert the Node.js/<major> prefix. SDK behavior is unchanged.

Worth knowing: requests from Node 21+ already send only the Node major version and no runtime_env, so anything that reads runtime_env from the User-Agent for analytics is missing those users today.

Why a major version

Yarn 1 enforces dependency engines by default, as do npm and pnpm with engine-strict. Released as 4.x, this would break installs for anyone on Node 18/20 with a ^4 range.

Testing

• Unit tests: 349/349 pass on Node 22.23.3, 24.21.0 and 26.10.0. These ran locally with ts-jest type-checking off, because the local node_modules had drifted from the lockfile (TypeScript 5.9 vs 5.4). CI covers type-checking.
• Build, eslint, tsc and publint pass; prettier is clean on the changed files.
• Integration tests weren't run.

Notes

• feat(streaming): add speakerLabelsRevisionIntervalMs param #188 also bumps the version (to 4.41.5) and adds a CHANGELOG entry, so whichever PR merges second needs a rebase. If this one lands first, feat(streaming): add speakerLabelsRevisionIntervalMs param #188 ships in 5.x and won't reach Node 18/20 users.
• Follow-ups, left out to keep 5.0.0 free of runtime changes: src/utils/live.ts still has two Node 18/20 workarounds (Math.random for multipart boundaries, and a hand-rolled deadlineSignal instead of AbortSignal.any, which would also raise the minimum Safari version to 17.4), and @types/node is still ^18.

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