feat(tools): add LEGO importer using Rebrickable API

- Implement  to add sets by query or ID
- Interactive selection, set/theme fetch, image downloads
- Include minifig images and YAML with title + attribution
- Persist API responses under tools/cache/rebrickable (gitignored)
- Add tools/config.json for API key

.gitignore

@@ -2,4 +2,5 @@ node_modules
 .hugo_build.lock
 resources/
 public/
-.DS_Store
+.DS_Store
+tools/cache/