Add workflow proof and example debriefs

[KyleBrierley]

What changed

• add a GitHub-rendered exercise-run-review workflow visual
• add two concise example debriefs for instruction writing and diff hygiene
• label the examples as illustrative evidence, not transcripts or benchmarks

Why

Make the repository easier for recruiters and practitioners to scan while showing the operating discipline behind the exercises.

Validation

• npm test in all three JavaScript fixtures
• git diff --check
• final status and diff review