[Demo] Add example reports, terminal recording, and final case study

[Dyu20705]

Problem statement

The portfolio should show the CLI solving a real-like CI failure, not just describe it.

Implementation notes

Add example triage reports generated from fixtures, a terminal recording or screenshots, and a case study describing architecture, classification tradeoffs, observability, and limitations.

Checklist

• Generate example reports from fixtures
• Capture terminal recording or screenshots
• Write final case study
• Document limitations and future work
• Link demo assets from README

Acceptance criteria

• Demo artifacts are reproducible from fixture commands
• Case study explains evidence-based triage and CI reliability
• README links to reports and demo assets
• Limitations are honest and specific

Epic

#21