perf improvement for db cleanup

routes/_utils/database/cleanup.js

@@ -14,6 +14,9 @@ async function cleanup(instanceName, timeline) {
 
     store.count().onsuccess = (e) => {
       let count = e.target.result
+      if (count <= MAX_NUM_STORED_STATUSES) {
+        return
+      }
       let openKeyCursor = index.openKeyCursor || index.openCursor
       openKeyCursor.call(index, null, 'prev').onsuccess = (e) => {
         let cursor = e.target.result

routes/_utils/database/database.js

@@ -1,5 +1,5 @@
 import { cleanupOldStatuses } from './cleanup'
-import { OBJECT_STORE, getDatabase, doTransaction } from './shared'
+import { OBJECT_STORE, getDatabase } from './shared'
 import { toReversePaddedBigInt, transformStatusForStorage } from './utils'
 
 export async function getTimeline(instanceName, timeline, maxId = null, limit = 20) {