feat: add official furnidata sync button for importing all missing items

- API endpoint: /api/admin/import/official/sync-all
  - Fetches all official Habbo furnidata
  - Compares with database to find missing items
  - Imports missing items via SSE batch with progress reporting
  - 500 item limit for safety
  - Proper abort signal support
- Client component: OfficialSyncClient with progress UI
- Updated StudioSyncPage to include Official Furnidata sync option
- Uses existing importSingleFurni infrastructure

src/app/api/admin/import/official/sync-all/route.ts

@@ -0,0 +1,97 @@
+import { withAdmin } from "@/lib/api-handler";
+import { db, ItemsBase } from "@/lib/db";
+import { PERMS } from "@/lib/permissions";
+import { importSingleFurni } from "@/lib/services/furni-import";
+import { getOfficialHabboFurnidata } from "@/lib/services/habbo-furnidata-cache";
+import { runSseBatch } from "@/lib/services/import/core/sse-batch";
+
+export const POST = withAdmin(
+	{ permission: PERMS.ASSETS_IMPORT },
+	async (request) => {
+		// Haal alle officiële furnidata
+		const furnidata = await getOfficialHabboFurnidata();
+
+		// Haal alle bestaande classnames uit de database
+		const existingClassnames = new Set(
+			await db
+				.select({ itemName: ItemsBase.itemName })
+				.from(ItemsBase)
+				.then((rows) => rows.map((r) => r.itemName)),
+		);
+
+		// Filter naar alleen items die niet in de database staan
+		const missingItems = Array.from(furnidata.entries())
+			.filter(([, entry]) => !existingClassnames.has(entry.classname))
+			.map(([, entry]) => ({
+				classname: entry.classname,
+				name: entry.name,
+				description: entry.description ?? "",
+				type: entry.category === "wallitem" ? "wallitem" : "flooritem",
+				revision: entry.revision ?? 0,
+				category: entry.category ?? "unknown",
+			}));
+
+		if (missingItems.length === 0) {
+			return new Response(
+				JSON.stringify({
+					success: true,
+					message: "All items are already in the database",
+					imported: 0,
+				}),
+				{
+					headers: { "Content-Type": "application/json" },
+				},
+			);
+		}
+
+		if (missingItems.length > 500) {
+			return new Response(
+				JSON.stringify({
+					success: false,
+					message: `Too many missing items (${missingItems.length}). Consider importing in smaller batches.`,
+				}),
+				{
+					headers: { "Content-Type": "application/json" },
+					status: 400,
+				},
+			);
+		}
+
+		// Importeren via SSE batch
+		return runSseBatch({
+			items: missingItems,
+			concurrency: 3,
+			signal: request.signal,
+			labelOf: (it) => it.classname,
+			worker: async (it, _index, report) => {
+				const result = await importSingleFurni({
+					id: 0,
+					classname: it.classname,
+					name: it.name,
+					description: it.description,
+					type: it.type,
+					revision: it.revision,
+					category: it.category,
+					onProgress: report,
+				});
+
+				if (result.ok) {
+					return {
+						ok: true,
+						warnings: result.warnings,
+						error: result.error,
+					};
+				}
+
+				return {
+					ok: false,
+					warnings: result.warnings,
+					error: result.error,
+				};
+			},
+			flush: async () => {
+				// FurnitureData.json wordt automatisch geschreven door importSingleFurni
+			},
+		});
+	},
+);