Frontend: 3D house map and inventory UI #203

Implement a React-based frontend user interface to:

• Upload/import room scans (GLB/USDZ or similar).
• View a 3D or 2D map of the home using three.js (or similar), displaying imported scans and detected anchors.
• List, add, and edit household items (inventory management).
• Allow attaching items to 3D anchor points via a visual interface.
• Show AI-suggested item locations/categories.
• Display scan and upload status, anchor linking, and inventory search/filter.

Acceptance:

• Users can view a 3D map and interact with anchors/items.
• Uploads and all UI actions work in conjunction with the backend endpoints.
• Ready for local run via Docker Compose and for expansion/mobility (PWA/mobile).