refactor(message): replace MessageStateManager with zustand store

- Remove MessageStateManager wrapper layer in favor of direct zustand store
- Move service modules to services/ subdirectory (ConversationOperations, MessageDeduplication, MessageSendService, MessageSyncService, ReadReceiptManager, UserCacheService, WSMessageHandler)
- Add new zustand-based store with subscriptionManager for event handling
- Introduce React hooks for message state (useConversations, useMessages, useUnreadCount, etc.)
- Update exports in index.ts to reflect new module structure
- Deprecate messageManager.ts entry point in favor of message/index.ts
- Maintain backward compatibility with existing MessageManager API

src/stores/message/services/MessageDeduplication.ts

@@ -0,0 +1,61 @@
+/**
+ * 消息去重服务
+ * 处理消息去重逻辑，防止重复处理相同的消息
+ */
+
+import type { IMessageDeduplication } from '../types';
+import {
+  PROCESSED_MESSAGE_ID_EXPIRY,
+  PROCESSED_MESSAGE_ID_MAX_SIZE,
+} from '../constants';
+
+export class MessageDeduplication implements IMessageDeduplication {
+  // 已处理消息ID集合（用于去重，防止ACK消息和正常消息重复处理）
+  private processedMessageIds: Set<string> = new Set();
+  private processedMessageIdsExpiry: Map<string, number> = new Map();
+
+  /**
+   * 检查消息是否已处理
+   */
+  isMessageProcessed(messageId: string): boolean {
+    return this.processedMessageIds.has(messageId);
+  }
+
+  /**
+   * 标记消息已处理
+   */
+  markMessageAsProcessed(messageId: string): void {
+    this.processedMessageIds.add(messageId);
+    this.processedMessageIdsExpiry.set(messageId, Date.now());
+    
+    // 定期清理
+    if (this.processedMessageIds.size > PROCESSED_MESSAGE_ID_MAX_SIZE) {
+      this.cleanupProcessedMessageIds();
+    }
+  }
+
+  /**
+   * 清理过期的消息ID（防止内存泄漏）
+   */
+  cleanupProcessedMessageIds(): void {
+    const now = Date.now();
+    for (const [id, timestamp] of this.processedMessageIdsExpiry.entries()) {
+      if (now - timestamp > PROCESSED_MESSAGE_ID_EXPIRY) {
+        this.processedMessageIds.delete(id);
+        this.processedMessageIdsExpiry.delete(id);
+      }
+    }
+  }
+
+  /**
+   * 重置所有已处理的消息ID
+   * 用于测试或需要清除缓存的场景
+   */
+  reset(): void {
+    this.processedMessageIds.clear();
+    this.processedMessageIdsExpiry.clear();
+  }
+}
+
+// 单例导出
+export const messageDeduplication = new MessageDeduplication();