chore(node): pin runtime and types to the Node 24 LTS line

[chriskehayias]

Pins the project to a single Node major so local, CI, and Vercel all run the same runtime.

Why

engines.node was a three-arm range (^22.22.2 || ^24.15.0 || >=26.0.0), which let every environment pick a different arm. Vercel only offers major versions — 24.x (its current default), 22.x, 20.x — and engines.node overrides the project's Build & Deployment setting, so the deployed runtime was effectively 24 while nothing else guaranteed it.

@types/node was at ^26.5.1, two majors ahead of what actually runs. Typings for APIs that don't exist in the deployed Node compile clean and fail at request time.

Changes

File	Change
package.json	engines.node → ^24.15.0; @types/node ^26.5.1 → ^24.13.4
.nvmrc (new)	24
.github/workflows/test.yml	node-version: 24 → node-version-file: .nvmrc — removes the second hardcoded copy
scripts/setup.ts	REQUIRED_NODE_VERSION = 20 → REQUIRED_NODE_MAJOR/MINOR (24/15); getNodeVersion() returns { major, minor }. Now rejects any major other than 24, not just older ones — someone on 26 previously passed setup while deploying to 24.
CLAUDE.md	Node bullet rewritten with the pin and the condition that releases it; @types/node 25+ row added to Current holds
README.md	Prerequisite is now v24.15.0+ on the 24.x line, .nvmrc-driven

The 24.15 floor is jsdom 30's requirement (strictest dev dependency); every 24.x Vercel ships satisfies it.

Vercel coverage

engines.node: ^24.15.0 resolves to the latest 24.x on Vercel and overrides the dashboard setting, covering both builds and functions. There is no Node-version field in vercel.json, so no such file was added — engines is the correct and complete mechanism. See Supported Node.js versions.

Hold condition

Hold this pin until Vercel's default Node version moves forward. Then bump engines.node, .nvmrc, @types/node, and REQUIRED_NODE_MAJOR in scripts/setup.ts together.

Verification

• npm install clean — 0 vulnerabilities
• npm run test:run — 812 tests / 50 files pass
• eslint . — clean
• npm run setup:check — [1/8] Node.js version... ✓ v24.18.0

⚠️ Pre-existing, unrelated: tsc --noEmit reports 18 type errors in MP provider test files (CommunicationInfo / MessageInfo / FileUploadParams shape mismatches). The count is identical before and after this change. Since CI gates tests only, npm run build is already broken on dev independently of this PR.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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