- Add category image API methods (upload/delete) to src/api/index.js
- Add uploadCategoryImage/deleteCategoryImage thunks and extraReducers in categorySlice
- Add CategoryBackdrop component showing ThumbHash placeholder with full thumb overlay
- Add photo upload/delete tab to CategoryEditTile settings cycle
- Category tile label band uses semi-transparent black overlay with white text
- Pass thumbHash/fullHash to both CategoryTile and CategoryEditTile