feat(22-01): add UIStore modal states, AddToCollectionModal, and sonner toasts

- Extend UIStore with addToCollectionModal, addToThreadModal, catalogSessionThreadId
- Create AddToCollectionModal with category dropdown, notes, purchase price
- Install sonner and add Toaster + AddToCollectionModal to root layout
- closeCatalogSearch now resets catalogSessionThreadId

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package.json

@@ -51,6 +51,7 @@
 		"react": "^19.2.4",
 		"react-dom": "^19.2.4",
 		"recharts": "^3.8.0",
+		"sonner": "^2.0.7",
 		"tailwindcss": "^4.2.1",
 		"zod": "^4.3.6",
 		"zustand": "^5.0.11"