docs: add lab2 submission — Threagile threat modeling

[blxxdclxud]

Goal

Lab 2 — Threat modeling of OWASP Juice Shop using Threagile. Generated baseline and secure variant models, analyzed risks, and compared results.

Changes

• Added Threagile baseline model outputs (labs/lab2/baseline/)
• Created secure model variant (labs/lab2/threagile-model.secure.yaml) with HTTPS + storage encryption
• Added secure variant outputs (labs/lab2/secure/)
• Added labs/submission2.md with risk analysis and delta comparison

Testing

• Local testing performed
• Verified the expected behavior

Artifacts & Screenshots

• Baseline: labs/lab2/baseline/ (report.pdf, diagrams, risks.json, stats.json, technical-assets.json)
• Secure: labs/lab2/secure/ (same set of files)

---

Checklist

• PR has a clear, descriptive title
• Documentation updated if needed
• No secrets or large temp files included
• Task 1 done — Threagile baseline model + risk analysis
• Task 2 done — HTTPS variant + risk comparison