feat: Add engine compatibility check for PRs

[d3xter666]

Reusable workflow that runs npm ci --dry-run against boundary Node versions and posts a consolidated PR comment with incompatible packages. Adds blocked label on failure with detailed Github Bot comment with the failing packages and their node engines.

Approaches evaluated:

• npm ci --engine-strict: runtime check only, stops at first failure, misses remaining incompatible packages
• check-engine (npm): only checks running Node against root engines, doesn't inspect dependency tree
• check-engine-light (npm): range-vs-range via semver.subset(), but v0.x, only 4 releases, unstable
• ls-engines (npm): range-vs-range capable, but v0.x, 17-month release gap, 7 prod dependencies

Selected approach: single-job nvm loop using npm ci --dry-run (without --engine-strict). Reports all EBADENGINE warnings as a table in one PR comment. No extra dependencies, no matrix, no artifacts — just shell and tools already on the runner.
Note: NVM seems to come bundled in the GitHub action images

PoC of the implementation: d3xter666/test-ci#1
JIRA: CPOUI5FOUNDATION-1225

[github-actions]

✅ Engine Compatibility

Node	Result	Incompatible Packages
v22.20.0	✅ Pass	—
v22.22.2	✅ Pass	—
v24.0.0	✅ Pass	—
v24.14.1	✅ Pass	—

[d3xter666]

Note: This flow can be ruesed accross repositories the following way:

uses: UI5/cli/.github/workflows/engine-compat.yml@main
with:
  node-versions: '20, 22, 24'

The caller uses owner/repo/.github/workflows/file.yml@ref syntax instead of ./.github/workflows/...
No copying needed. The @ main can also be a tag (@ v1) or SHA for pinning.

I gave it a try in an external repositorty and it seems to be working correctly:

• https://github.com/d3xter666/test-ci/pull/1/changes#diff-86c810903f8631220438a8f9ec529ccb2ac3f52ca950cc95a999397077deb106R18
• https://github.com/d3xter666/test-ci/actions/runs/24188653031/job/70599746155