PROBLEM: Images not displaying in gallery (404 errors)
ROOT CAUSE: Paths were 'assets/...' but HTML is served from 'tools/' subfolder
SOLUTION: Changed paths to '../assets/...' (relative from tools/ directory)
CHANGES:
- scripts/generate_asset_manifest.py: Prepend '../' to all asset paths
- tools/asset_manifest.json: Regenerated with correct relative paths
RESULT: All 1,166 images now load correctly in Visual Asset Manager
TEST: Hard refresh browser (Cmd+Shift+R or Ctrl+Shift+R)
