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

tools/config.json

@@ -0,0 +1,5 @@
+{
+  "rebrickable": {
+    "apiKey": ""
+  }
+}