chore: update Node.js suport matrix to 22+

[kopernic-pl]

This pull request updates the project's Node.js support to require newer versions and drops support for older versions. The main focus is on aligning the codebase, documentation, CI workflows, and Docker image to require Node.js 22.9.0 or later, with expanded testing for even newer versions.

Node.js version updates:

• Updated the minimum required Node.js version in package.json to >=22.9.0 and removed support for Node.js 20.x.
• Updated the Node.js version in the Dockerfile from node:20-alpine to node:24-alpine.
• Updated documentation in README.md to state Node.js 22.9 or later is required.
• Updated the bug report issue template to reference Node.js 22.9.0 as the example version.

CI/CD workflow updates:

• Updated Node.js versions in GitHub Actions workflows:
  • build-main.yaml and pull-request.yaml: Now test against Node.js 22.x, 24.x, and 26.x (removed 20.x). [1] [2]
  • deploy-release.yaml and release-on-github.yaml: Now use Node.js 24.x for publishing and release jobs (was 20.x). [1] [2]