Fix TypeScript errors and implement furniture import ID integrity with 18+ age verification

- Add termsAccepted and ageVerified columns to User table
- Update register schema with new boolean fields
- Fix register form age verification checkbox (th -> t)
- Fix furni-import spriteId declaration order
- Fix batch route variable naming (id -> spriteId)
- Fix catalog-audit import path and ensure correct types
- Hardened import with per-item id conflict checks
- Added audit option for FurnitureData.json spriteId conflicts
- Updated tagline to include Leeftijdsvereiste: 18+

src/lib/services/furni-import.ts

@@ -14,6 +14,7 @@ import {
 import {
 	appendFurniEntry,
 	buildFurniEntry,
+	findFurniDataIdConflict,
 	removeFurniEntry,
 } from "@/lib/services/furni-data";
 import {
@@ -472,6 +473,16 @@ export async function importSingleFurni(params: {
 		};
 	}
 
+	// ── Check if spriteId already used in FurnitureData.json ──
+	const takenBy = await findFurniDataIdConflict(originalId, classname);
+	if (takenBy) {
+		return {
+			ok: false,
+			warnings,
+			error: `spriteId ${originalId} already used by "${takenBy}" in FurnitureData.json`,
+		};
+	}
+
 	const itemType = type === "wallitem" ? "i" : "s";
 	const spriteId = originalId;