Convert to using the node test runner

[bcomnes]

Converts the test suite to use the nodejs test runner.

[bcomnes]

Used an agent to help with this, still need to line by line review it, but overall looks decent.

[bcomnes]

Reminder that the node test runner runs concurrently by default.

[Copilot]

Pull Request Overview

This pull request converts the test suite to use Node’s native test runner rather than the previous mocha‐based runner. Key changes include updating assertions and test declarations to use the new Node test runner API, updating package scripts and workflow configurations, and adjusting configuration files (such as ESLint and Knip) to accommodate these changes.

Reviewed Changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
test/*.js (all test files)	Replaces require('assert').strict with node:assert/strict and converts "it" to "test" using the node:test module.
package.json	Updates test and watch scripts to use node’s test runner instead of mocha.
eslint.config.js	Adds "node" environment support alongside mocha.
.knip.jsonc	Updates ignored dependencies by adding "spec".
.github/workflows/test.yml	Changes the test command to "npm run test" in the CI workflow.

[bcomnes]

Read through it. Looks good, tests are passing. Let's try it.