feat(aia): Complete AIA V2.0 with universal streaming capabilities

Major Updates:
- Add StreamingService with OpenAI Compatible format (backend/common/streaming)
- Upgrade Chat component V2 with Ant Design X integration
- Implement AIA module with 12 intelligent agents
- Create AgentHub with 100% prototype V11 restoration
- Create ChatWorkspace with streaming response support
- Add ThinkingBlock for deep thinking display
- Add useAIStream Hook for OpenAI Compatible stream handling

Backend Common Capabilities (~400 lines):
- OpenAIStreamAdapter: SSE adapter with OpenAI format
- StreamingService: unified streaming service
- Support content and reasoning_content dual streams
- Deep thinking tag processing (<think>...</think>)

Frontend Common Capabilities (~2000 lines):
- AIStreamChat: modern streaming chat component
- ThinkingBlock: collapsible deep thinking display
- ConversationList: conversation management with grouping
- useAIStream: OpenAI Compatible stream handler Hook
- useConversations: conversation state management Hook
- Modern design styles (Ultramodern theme)

AIA Module Frontend (~1500 lines):
- AgentHub: 12 agent cards with timeline design
- ChatWorkspace: fullscreen immersive chat interface
- AgentCard: theme-colored cards (blue/yellow/teal/purple)
- 5 phases, 12 agents configuration
- Responsive layout (desktop + mobile)

AIA Module Backend (~900 lines):
- agentService: 12 agents config with system prompts
- conversationService: refactored with StreamingService
- attachmentService: file upload skeleton (30k token limit)
- 12 API endpoints with authentication
- Full CRUD for conversations and messages

Documentation:
- AIA module status and development guide
- Universal capabilities catalog (11 services)
- Quick reference card for developers
- System overview updates

Testing:
- Stream response verified (HTTP 200)
- Authentication working correctly
- Auto conversation creation working
- Deep thinking display working
- Message input and send working

Status: Core features completed (85%), attachment and history loading pending

backend/src/common/streaming/index.ts

@@ -0,0 +1,20 @@
+/**
+ * 通用流式响应服务 - 统一导出
+ * 
+ * 提供 OpenAI Compatible 格式的流式响应能力
+ * 支持 Ant Design X 的 XRequest 直接消费
+ */
+
+export { OpenAIStreamAdapter, createOpenAIStreamAdapter } from './OpenAIStreamAdapter';
+export { StreamingService, createStreamingService, streamChat } from './StreamingService';
+
+export type {
+  OpenAIMessage,
+  OpenAIStreamChunk,
+  StreamOptions,
+  StreamCallbacks,
+  SSEEventType,
+} from './types';
+
+export { THINKING_TAGS } from './types';
+