chore: 統一 可選成員 寫法

client/api/client_data/RecentChat.ts

@@ -1,6 +1,6 @@
 export default class RecentChat {
     declare id: string
     declare title: string
-    declare avatar: string | null
+    declare avatar?: string
     declare content: string
 }

server/data/User.ts

@@ -106,7 +106,7 @@ export default class User {
         User.database.prepare(`UPDATE ${User.table_name} SET ${key} = ? WHERE count = ?`).run(value, this.bean.count)
         this.bean[key] = value
     }
-    getUserName(): string | null {
+    getUserName() {
         return this.bean.username
     }
     setUserName(userName: string) {

server/data/UserBean.ts

@@ -2,10 +2,10 @@ export default class UserBean {
     declare count: number
     declare id: string
     declare password: string
-    declare username: string | null
+    declare username?: string
     declare registered_time: number
     declare nickname: string
-    declare avatar_file_hash: string | null
+    declare avatar_file_hash?: string
     declare settings: string
 
     [key: string]: unknown