feat(im-sdk): 添加 Flutter IM SDK 和 Go 服务端 SDK

- 实现了完整的 Flutter IM SDK，支持消息发送、历史记录、会话管理、好友功能和群组操作
- 添加了 Go 服务端 SDK 骨架，包含登录、消息发送、撤回、编辑等核心功能
- 实现了认证和授权机制，支持 token 管理和请求签名验证
- 添加了会话列表、好友申请、群组管理和消息搜索功能
- 提供了用户资料管理、头像上传和账户导入导出功能
- 实现了消息撤回、编辑和已读状态管理功能
- 添加了群组加入申请、审批和成员管理功能
- 提供了消息历史分页查询和定位功能
- 实现了会话置顶、免打扰和草稿保存功能
- 添加了用户和群组搜索功能，支持关键词检索

src/im/api.ts

@@ -187,6 +187,14 @@ export function getGroupInfo(groupId: string): Promise<ImGroup> {
   return http.get<ImGroup>(`/api/im/groups/${encodeURIComponent(groupId)}`, appQuery())
 }
 
+export function listGroupMembers(groupId: string): Promise<UserProfile[]> {
+  return http.get<UserProfile[]>(`/api/im/groups/${encodeURIComponent(groupId)}/members`, appQuery())
+}
+
+export function searchGroupMembers(groupId: string, keyword: string, size = 20): Promise<UserProfile[]> {
+  return http.get<UserProfile[]>(`/api/im/groups/${encodeURIComponent(groupId)}/members/search`, appQuery({ keyword, size }))
+}
+
 export function sendFriendRequest(toUserId: string, remark?: string): Promise<FriendRequest> {
   return http.post<FriendRequest>(
     '/api/im/friend-requests',

src/im/useIm.ts

@@ -52,6 +52,20 @@ export function useIm() {
     messages.value = [...messages.value, message]
   }
 
+  function markMessageRevoked(msgId: string) {
+    const index = messages.value.findIndex((item) => item.id === msgId)
+    if (index < 0) return
+    const next = [...messages.value]
+    next[index] = {
+      ...next[index],
+      status: 'REVOKED',
+      msgType: 'REVOKED',
+      revoked: true,
+      content: '',
+    }
+    messages.value = next
+  }
+
   async function refreshConversations() {
     const items = await listConversations()
     conversations.value = [...items].sort((a, b) => {
@@ -60,6 +74,14 @@ export function useIm() {
     })
   }
 
+  function markConversationRead(targetId: string, chatType: ChatType = 'SINGLE') {
+    conversations.value = conversations.value.map((item) =>
+      item.targetId === targetId && item.chatType === chatType
+        ? { ...item, unreadCount: 0 }
+        : item,
+    )
+  }
+
   async function loadHistory(toId: string, query: HistoryQuery = {}): Promise<PageResult<ImMessage>> {
     return fetchHistory(toId, query)
   }
@@ -91,6 +113,10 @@ export function useIm() {
       upsertMessage(msg)
       void refreshConversations().catch(() => {})
     })
+    im.on('revoke', ({ msgId }) => {
+      markMessageRevoked(msgId)
+      void refreshConversations().catch(() => {})
+    })
     im.on('error', (e) => { error.value = e })
     im.connect()
     client.value = im
@@ -105,11 +131,19 @@ export function useIm() {
   }
 
   function revoke(msgId: string) {
-    return revokeMessage(msgId)
+    return revokeMessage(msgId).then((message) => {
+      upsertMessage(message)
+      void refreshConversations().catch(() => {})
+      return message
+    })
   }
 
   function edit(msgId: string, content: string) {
-    return editMessage(msgId, content)
+    return editMessage(msgId, content).then((message) => {
+      upsertMessage(message)
+      void refreshConversations().catch(() => {})
+      return message
+    })
   }
 
   function disconnect() {
@@ -119,6 +153,8 @@ export function useIm() {
   }
 
   function setConversationRead(targetId: string, chatType: ChatType = 'SINGLE') {
+    markConversationRead(targetId, chatType)
+    void refreshConversations().catch(() => {})
     return markRead(targetId, chatType)
   }