feat(asl): Add DeepSearch smart literature retrieval MVP

Features:
- Integrate unifuncs DeepSearch API (OpenAI compatible protocol)
- SSE real-time streaming for AI thinking process display
- Natural language input, auto-generate PubMed search strategy
- Extract and display PubMed literature links
- Database storage for task records (asl_research_tasks)

Backend:
- researchService.ts - Core business logic with SSE streaming
- researchController.ts - SSE stream endpoint
- researchWorker.ts - Async task worker (backup mode)
- schema.prisma - AslResearchTask model

Frontend:
- ResearchSearch.tsx - Search page with unified content stream
- ResearchSearch.css - Styling (unifuncs-inspired simple design)
- ASLLayout.tsx - Enable menu item
- api/index.ts - Add research API functions

API Endpoints:
- POST /api/v1/asl/research/stream - SSE streaming search
- POST /api/v1/asl/research/tasks - Async task creation
- GET /api/v1/asl/research/tasks/:taskId/status - Task status

Documentation:
- Development record for DeepSearch integration
- Update ASL module status (v1.5)
- Update system status (v3.7)

Known limitations:
- SSE mode, task interrupts when leaving page
- Cost ~0.3 RMB per search (unifuncs API)

frontend-v2/src/modules/asl/api/index.ts

@@ -436,6 +436,48 @@ export async function exportFulltextResults(
   return response.blob();
 }
 
+// ==================== 智能文献检索API (DeepSearch) ====================
+
+/**
+ * 创建智能文献检索任务
+ */
+export async function createResearchTask(data: {
+  projectId: string;
+  query: string;
+}): Promise<ApiResponse<{
+  id: string;
+  status: string;
+}>> {
+  return request('/research/tasks', {
+    method: 'POST',
+    body: JSON.stringify(data),
+  });
+}
+
+/**
+ * 获取智能文献检索任务状态
+ */
+export async function getResearchTaskStatus(
+  taskId: string
+): Promise<ApiResponse<{
+  taskId: string;
+  status: 'processing' | 'ready' | 'error';
+  progress: number;
+  query?: string;
+  resultCount?: number;
+  reasoningContent?: string;
+  literatures?: Array<{
+    pmid: string;
+    title: string;
+    authors: string;
+    journal: string;
+    year: number;
+  }>;
+  errorMessage?: string;
+}>> {
+  return request(`/research/tasks/${taskId}/status`);
+}
+
 // ==================== 统一导出API对象 ====================
 
 /**
@@ -482,4 +524,8 @@ export const aslApi = {
   
   // 健康检查
   healthCheck,
+  
+  // 智能文献检索 (DeepSearch)
+  createResearchTask,
+  getResearchTaskStatus,
 };