docs: add filter to qa workflow

[medubelko]

Add conditionals to skip required checks and unnecessary operations.

For a reason I don't understand right now, the test job is hanging on my fork: medubelko#1. Normally I can test it just fine.

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• I've followed the contribution guidelines.
• I've signed the CLA.
• I've successfully run make lint && make test.
• I've added or updated any relevant documentation.
• In documents I changed, I added a meta description if one was missing.
• I've updated the relevant release notes.

[Copilot]

Pull request overview

Adds a path-based filter stage to the QA GitHub Actions workflow so downstream reusable lint/test workflows can conditionally skip work (e.g., on docs-only changes).

Changes:

• Introduces a filter job using dorny/paths-filter to compute a source-files output.
• Wires lint and test jobs to depend on filter and forwards the computed source-files value as an input.

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[medubelko]

@bepri This one is throwing me another curve ball. I don't know why the matrixed test jobs aren't starting on my fork. All my other forks were able to prove this code works on docs-only changes.

[lengau]

@medubelko if you mean the fact that the tests are running here, it's because qa.yaml got changed. When we modify a workflow that workflow should always run.

[lengau]

[per in-person conversation, I misunderstood. The specific items not running in @medubelko's fork is because they're waiting for a self-hosted runner tag that doesn't exist for his user account]