refactor: migrate to Node.js native test runner and fix runtime bugs

[Claude]

Migrates from Vitest to Node.js native test runner, simplifies build system, and fixes critical post-action bugs causing CI failures.

Testing Framework Migration

• Node.js native test runner (node:test) replaces Vitest
  • Timer mocking with mock.timers.enable() - tests run in ~400ms vs 21+ seconds
  • Module mocking via mock.module() for systeminformation
  • Updated assertions to node:assert/strict

// Tests now use mocked timers instead of real delays
before(async () => {
  mock.timers.enable({ apis: ['setTimeout', 'Date'] });
  ({ Metrics } = await import("./metrics.ts"));
});

await mock.timers.tick(5000);  // Instant time advancement

Package Management & Build

• npm replaces pnpm - removed pnpm-lock.yaml, updated all workflows
• Simplified build - removed source maps, prettier integration, wrapper files
• Dependencies cleaned - removed 20+ unused devDeps (textlint, vitest, prettier)
• Action entry points - direct bundle files (dist/main/index.bundle.js)

Bug Fixes

Port race condition (6f43b75)

• get-port allocated different ports per process → ECONNREFUSED
• Fixed to port 7777 in src/lib.ts

AbortError in post action (3cddd03)

• Used promise-based setTimeout from node:timers/promises instead of callback-based
• Caused uncaught AbortError on clearTimerController.abort()

// Before: promise-based setTimeout with signal
const timer = setTimeout(10 * 1000, () => controller.abort(), { signal });
clearTimerController.abort();  // Throws AbortError

// After: callback-based setTimeout
import { setTimeout as setTimeoutCallback } from "node:timers";
const timer = setTimeoutCallback(() => controller.abort(), 10 * 1000);
clearTimeout(timer);  // Proper cleanup

Configuration

• .node-version: 24.13.0 → 24
• action.yml: updated branding, author, entry points
• Removed: vitest.config.ts, eslint.config.mjs, unused build scripts
• Added: .github/workflows/copilot-setup-steps.yml

Breaking Changes

None - external API unchanged.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• https://api.github.com/graphql
  • Triggering command: /usr/bin/gh gh pr view claude/convert-to-native-node-test-REDACTED --json title,body,number /home/REDACTED/.nvm/install.sh /home/REDACTED/.nvm/nvm-exec /home/REDACTED/.nvm/nvm.sh /home/REDACTED/.nvm/package.json /home/REDACTED/.nvm/rename_test.sh /home/REDACTED/.nvm/test /hom�� (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)