fix(security): remove lab photos from public repo (#29)

## Summary
- Remove 26 orphaned lab instrument photos (IMG_3297-3322.jpg) that
could identify the physical lab location
- Add `lab-instruments/jpg/` to .gitignore to prevent re-addition
- Originals preserved in private backup

## Context
No code references these files. They were uploaded during early
development and pose a privacy/security risk in a public repo.

## Test plan
- [x] Verify no code imports or references these image paths
- [x] Confirm backup exists in labclaw-private
- [x] .gitignore updated to prevent re-addition

Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Cong <72737794+robolearning123@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 3 people

.gitignore

@@ -30,6 +30,9 @@ Thumbs.db
 *.HEIC
 *.heic
 
+# Lab photos (moved to private backup)
+lab-instruments/jpg/
+
 # Reference repos (submodules)
 Agent-S/
 UFO/