chore: switch to pnpm and native node test

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[Copilot]

Pull request overview

This PR modernizes the project's testing infrastructure by migrating from Mocha/Chai to Node.js native test runner, and switching from npm to pnpm as the package manager.

Key Changes:

• Replaced Mocha/Chai test framework with Node.js native node:test and node:assert/strict
• Migrated package manager from npm to pnpm
• Updated test descriptions to use active voice instead of "should" statements

Reviewed changes

Copilot reviewed 6 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/move-operations.spec.ts	Migrated test imports and assertions from Chai to Node.js native testing APIs; updated test descriptions
src/index.ts	Added exports for move operations functions
src/index.spec.ts	Converted all test assertions from Chai to Node.js assert; replaced @ts-ignore with @ts-expect-error; renamed shadowing variables
package.json	Updated package manager to pnpm; replaced test scripts to use native Node test runner; removed Mocha/Chai dependencies
.github/workflows/test.yml	Updated CI to use pnpm and newer action versions; changed Node.js test matrix
.github/workflows/semantic-release.yml	Updated release workflow to use pnpm instead of npm

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