Do not activate full CI run when only documents are changed

## Brief feature description

It is not necessary to do a full CI run when a pull request contains only non source code files.
Could we introduce an allowed-list of file types which do not trigger the CI, like markdown documents? This means, when a PR consists only of file types from that allowed-list the CI checks only the bare minimum like ECA, checklist etc.

This may improve the review speed and relieves some stress on the CI.

The issue names no CI workflow files, tests, or entry points; start by locating the repository's CI configuration and its current pull-request triggers. Define the allowed non-source file list and verify that documentation-only PRs run only the stated minimum checks while source changes still trigger the full CI run.

Written by the indexing model from the issue text.