feat(asl): Complete Deep Research V2.0 core development

Backend:
- Add SSE streaming client (unifuncsSseClient) replacing async polling
- Add paragraph-based reasoning parser with mergeConsecutiveThinking
- Add requirement expansion service (DeepSeek-V3 PICOS+MeSH)
- Add Word export service with Pandoc, inline hyperlinks, reference link expansion
- Add deep research V2 worker with 2s log flush and Chinese source prompt
- Add 5 curated data sources config (PubMed/ClinicalTrials/Cochrane/CNKI/MedJournals)
- Add 4 API endpoints (generate-requirement/tasks/task-status/export-word)
- Update Prisma schema with 6 new V2.0 fields on AslResearchTask
- Add DB migration for V2.0 fields
- Simplify ASL_DEEP_RESEARCH_EXPANSION prompt (remove strategy section)

Frontend:
- Add waterfall-flow DeepResearchPage (phase 0-4 progressive reveal)
- Add LandingView, SetupPanel, StrategyConfirm, AgentTerminal, ResultsView
- Add react-markdown + remark-gfm for report rendering
- Add custom link component showing visible URLs after references
- Add useDeepResearchTask polling hook
- Add deep research TypeScript types

Tests:
- Add E2E test, smoke test, and Chinese data source test scripts

Docs:
- Update ASL module status (v2.0 - core features complete)
- Update system status (v6.1 - ASL V2.0 milestone)
- Update Unifuncs DeepSearch API guide (v2.0 - SSE mode + Chinese source results)
- Update module auth specification (test script guidelines)
- Update V2.0 development plan

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/prisma/schema.prisma

@@ -477,7 +477,7 @@ model AslFulltextScreeningTask {
   @@schema("asl_schema")
 }
 
-/// 智能文献检索任务（DeepSearch）
+/// 智能文献检索任务（DeepSearch V1.x + V2.0）
 model AslResearchTask {
   id               String   @id @default(uuid())
   
@@ -486,23 +486,23 @@ model AslResearchTask {
   userId           String   @map("user_id")
   
   // 检索输入
-  query            String                           // 用户的自然语言查询
-  filters          Json?                            // 🔜 后续：高级筛选 { yearFrom, yearTo, articleTypes }
+  query            String                           // 用户的自然语言查询（V1.x 原始输入 / V2.0 Step 1 粗略想法）
+  filters          Json?                            // 高级筛选 { yearRange, targetCount, requireOpenAccess }
   
   // unifuncs 任务
   externalTaskId   String?  @map("external_task_id")
   
-  // 状态
-  status           String   @default("pending")     // pending/processing/completed/failed
+  // 状态: draft → pending → running → completed / failed
+  status           String   @default("pending")
   errorMessage     String?  @map("error_message")
   
-  // 结果
+  // V1.x 结果字段（保留向后兼容）
   resultCount      Int?     @map("result_count")
   rawResult        String?  @map("raw_result") @db.Text
-  reasoningContent String?  @map("reasoning_content") @db.Text  // AI思考过程
-  literatures      Json?                            // 解析后的文献列表
+  reasoningContent String?  @map("reasoning_content") @db.Text
+  literatures      Json?
   
-  // 统计（🔜 后续展示）
+  // 统计
   tokenUsage       Json?    @map("token_usage")
   searchCount      Int?     @map("search_count")
   readCount        Int?     @map("read_count")
@@ -513,6 +513,15 @@ model AslResearchTask {
   updatedAt        DateTime @updatedAt @map("updated_at")
   completedAt      DateTime? @map("completed_at")
 
+  // ── V2.0 新增字段 ──────────────────────────────
+  targetSources         Json?    @map("target_sources")          // 选中的数据源 ["https://pubmed.ncbi.nlm.nih.gov/", ...]
+  confirmedRequirement  String?  @map("confirmed_requirement") @db.Text  // 用户核验后的自然语言检索指令书
+  aiIntentSummary       Json?    @map("ai_intent_summary")       // PICOS + MeSH 结构化摘要
+  executionLogs         Json?    @map("execution_logs")          // 终端日志数组 [{type, title, text, ts}]
+  synthesisReport       String?  @map("synthesis_report") @db.Text // AI综合报告（Markdown）
+  resultList            Json?    @map("result_list")             // 结构化文献元数据列表
+
+  // ── 索引 ────────────────────────────
   @@index([projectId], map: "idx_research_tasks_project_id")
   @@index([userId], map: "idx_research_tasks_user_id")
   @@index([status], map: "idx_research_tasks_status")