Refactor, fix boolean cookie attributes, and add test coverage

[Copilot]

• Fix bug: boolean cookie attributes (Secure: true) emitted Secure=true instead of the spec-correct Secure; false values now correctly omit the attribute
• Refactor: extract _getCookiePattern(key) to eliminate duplicated regex construction in get() and isset()
• Simplify set() cookie string builder — replace reduce+initialValue with clean filter+map
• Add Vitest + jsdom test infrastructure (vitest.config.js, devDependencies, updated package.json test script)
• Add 32 comprehensive tests covering all public methods, namespace support, _qualify(), and _getCookiePattern()
• Add GitHub Actions workflow (.github/workflows/test.yml) that runs tests on every push and pull request

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[iamgergo]

@copilot Could you add a GH action as well that runs the tests?

[Copilot]

@copilot Could you add a GH action as well that runs the tests?

Added .github/workflows/test.yml in commit 41c0fa6. It triggers on every push and pull request, runs npm ci then npm test.