style: clean up code formatting and remove trailing whitespace

refactor: reorganize imports and fix type imports

lib/ai/token-usage.ts

@@ -13,7 +13,9 @@ export interface TokenUsageRecord {
 
 const KEY_PREFIX = "ai:usage";
 
-export async function recordTokenUsage(record: TokenUsageRecord): Promise<void> {
+export async function recordTokenUsage(
+  record: TokenUsageRecord,
+): Promise<void> {
   const redis = await getRedisClient();
   const dayKey = `${KEY_PREFIX}:day:${new Date(record.timestamp).toISOString().slice(0, 10)}`; // YYYY-MM-DD
   const listKey = `${KEY_PREFIX}:records`;
@@ -31,4 +33,4 @@ export async function recordTokenUsage(record: TokenUsageRecord): Promise<void>
   pipeline.lTrim(listKey, 0, 9999);
 
   await pipeline.exec();
-}
+}