feat(ssa): Complete Phase I-IV intelligent dialogue and tool system development

Phase I - Session Blackboard + READ Layer:
- SessionBlackboardService with Postgres-Only cache
- DataProfileService for data overview generation
- PicoInferenceService for LLM-driven PICO extraction
- Frontend DataContextCard and VariableDictionaryPanel
- E2E tests: 31/31 passed

Phase II - Conversation Layer LLM + Intent Router:
- ConversationService with SSE streaming
- IntentRouterService (rule-first + LLM fallback, 6 intents)
- SystemPromptService with 6-segment dynamic assembly
- TokenTruncationService for context management
- ChatHandlerService as unified chat entry
- Frontend SSAChatPane and useSSAChat hook
- E2E tests: 38/38 passed

Phase III - Method Consultation + AskUser Standardization:
- ToolRegistryService with Repository Pattern
- MethodConsultService with DecisionTable + LLM enhancement
- AskUserService with global interrupt handling
- Frontend AskUserCard component
- E2E tests: 13/13 passed

Phase IV - Dialogue-Driven Analysis + QPER Integration:
- ToolOrchestratorService (plan/execute/report)
- analysis_plan SSE event for WorkflowPlan transmission
- Dual-channel confirmation (ask_user card + workspace button)
- PICO as optional hint for LLM parsing
- E2E tests: 25/25 passed

R Statistics Service:
- 5 new R tools: anova_one, baseline_table, fisher, linear_reg, wilcoxon
- Enhanced guardrails and block helpers
- Comprehensive test suite (run_all_tools_test.js)

Documentation:
- Updated system status document (v5.9)
- Updated SSA module status and development plan (v1.8)

Total E2E: 107/107 passed (Phase I: 31, Phase II: 38, Phase III: 13, Phase IV: 25)

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

backend/src/modules/ssa/services/DataProfileService.ts

@@ -349,6 +349,66 @@ export class DataProfileService {
 
     return lines.join('\n');
   }
+
+  /**
+   * Phase I: 获取单变量详细分析（调用 Python variable-detail 端点）
+   *
+   * @param sessionId SSA 会话 ID
+   * @param variableName 目标变量名
+   */
+  async getVariableDetail(sessionId: string, variableName: string): Promise<any> {
+    try {
+      const csvContent = await this.loadCSVFromSession(sessionId);
+      if (!csvContent) {
+        return { success: false, error: 'No CSV data available for session' };
+      }
+
+      const response = await this.client.post('/api/ssa/variable-detail', {
+        csv_content: csvContent,
+        variable_name: variableName,
+        max_bins: 30,
+        max_qq_points: 200,
+      });
+
+      return response.data;
+    } catch (error: any) {
+      logger.error('[SSA:DataProfile] Variable detail failed', {
+        sessionId, variableName, error: error.message,
+      });
+      return { success: false, error: error.message };
+    }
+  }
+
+  /**
+   * 从 Session 加载原始 CSV 字符串（供 variable-detail 复用）
+   */
+  private async loadCSVFromSession(sessionId: string): Promise<string | null> {
+    const session = await prisma.ssaSession.findUnique({ where: { id: sessionId } });
+    if (!session) return null;
+
+    if (session.dataOssKey) {
+      const buffer = await storage.download(session.dataOssKey);
+      return buffer.toString('utf-8');
+    }
+
+    if (session.dataPayload) {
+      const rows = session.dataPayload as unknown as Record<string, any>[];
+      if (rows.length === 0) return null;
+      const cols = Object.keys(rows[0]);
+      const lines = [cols.join(',')];
+      for (const row of rows) {
+        lines.push(cols.map(c => {
+          const v = row[c];
+          if (v === null || v === undefined) return '';
+          const s = String(v);
+          return s.includes(',') || s.includes('"') ? `"${s.replace(/"/g, '""')}"` : s;
+        }).join(','));
+      }
+      return lines.join('\n');
+    }
+
+    return null;
+  }
 }
 
 // 单例导出