feat(module-02): rewrite lab as fleet triage exercise with Platform AI tools

- Rename lab from 'Exploring AWS Platform AI Features' to 'Triaging a Broken Fleet'
- Add starter files: broken-fleet.yaml (instance configs), fleet-issues.md (known issues)
- Lab now focuses on using CloudWatch, Amazon Q, and DevOps Guru to diagnose misconfigurations
- Add .obsidian/ to .gitignore

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

Author: initcron

.gitignore

@@ -25,6 +25,7 @@ reference-app/dashboard/package-lock.json
 # OS
 .DS_Store
 Thumbs.db
+.obsidian/
 
 # Environment
 .env