fix: resolve pre-existing lint warnings

- Remove unused siteSettings import in auth-precheck.test.ts
- Replace non-null assertions with proper null checks in furni-data-i18n.ts
- Replace non-null assertions with proper null checks in conversion-pool.ts

src/lib/services/swf/conversion-pool.ts

@@ -79,8 +79,9 @@ function ensurePool(): boolean {
 
 function pump() {
 	while (idle.length > 0 && queue.length > 0) {
-		const w = idle.pop()!;
-		const job = queue.shift()!;
+		const w = idle.pop();
+		const job = queue.shift();
+		if (!w || !job) break;
 		pending.set(job.req.id, { worker: w, job });
 		w.postMessage(job.req);
 	}