Fix/release yml - #53

Description

This PR improves the GitHub Actions workflows for better consistency, performance, and reliability:

Workflow Improvements:

• Replace npm commands with pnpm for consistency with package.json (which specifies "packageManager": "pnpm@10.6.1")
• Add pnpm store caching to speed up dependency installation across all workflow jobs
• Use --frozen-lockfile for deterministic builds and faster CI runs
• Fix changelog link to point to release page instead of broken comparison URL
• Add proper pnpm setup across all workflow jobs for consistency

Testing Improvements:

• Replace fallback echo with proper test:run command using vitest
• Ensure test failures block releases as intended by using the correct test script
• Use vitest run mode for CI environment (non-watch mode)

These changes align the CI/CD pipeline with the project's actual package manager configuration and improve build reliability and performance.

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have added tests that prove my fix is effective or that my feature works
• The title of my pull request follows the conventional commits standard
• Changes have been documented in the README/documentation (if applicable)