fix(ssa): Fix 7 integration bugs and refactor frontend unified state management

Bug fixes:
- Fix garbled error messages in chat (TypeWriter rendering issue)
- Fix R engine NA crash in descriptive.R (defensive isTRUE/is.na checks)
- Fix intent misclassification for statistical significance queries
- Fix step 2 results not displayed (accept warning status alongside success)
- Fix incomplete R code download (only step 1 included)
- Fix multi-task state confusion (clicking old card shows new results)
- Add R engine and backend parameter logging for debugging

Refactor - Unified Record Architecture:
- Replace 12 global singleton fields with AnalysisRecord as single source of truth
- Remove isWorkflowMode branching across all components
- One Analysis = One Record = N Steps paradigm
- selectRecord only sets currentRecordId, all rendering derives from currentRecord
- Fix cross-hook-instance issue: executeWorkflow fallback to store currentRecordId

Updated files: ssaStore, useWorkflow, useAnalysis, SSAChatPane, SSAWorkspacePane,
SSACodeModal, WorkflowTimeline, QueryService, WorkflowExecutorService, descriptive.R

Tested: Manual integration test passed - multi-task switching, R code completeness
Co-authored-by: Cursor <cursoragent@cursor.com>

frontend-v2/src/modules/ssa/components/SSACodeModal.tsx

@@ -1,85 +1,79 @@
 /**
- * SSACodeModal - V11 R代码模态框
- * 
- * 100% 还原 V11 原型图
- * 调用后端 API 获取真实执行代码
+ * SSACodeModal - R 代码模态框 (Unified Record Architecture)
+ *
+ * 从 currentRecord.steps 聚合所有步骤的可复现代码。
  */
 import React, { useEffect, useState } from 'react';
 import { X, Download, Loader2 } from 'lucide-react';
 import { useSSAStore } from '../stores/ssaStore';
-import { useAnalysis } from '../hooks/useAnalysis';
 
 export const SSACodeModal: React.FC = () => {
-  const { codeModalVisible, setCodeModalVisible, executionResult, addToast, isWorkflowMode, workflowSteps } = useSSAStore();
-  const { downloadCode } = useAnalysis();
+  const {
+    codeModalVisible,
+    setCodeModalVisible,
+    addToast,
+    currentRecordId,
+    analysisHistory,
+  } = useSSAStore();
+
   const [code, setCode] = useState<string>('');
   const [isLoading, setIsLoading] = useState(false);
 
-  useEffect(() => {
-    if (codeModalVisible) {
-      loadCode();
-    }
-  }, [codeModalVisible]);
+  const record = currentRecordId
+    ? analysisHistory.find((r) => r.id === currentRecordId) ?? null
+    : null;
 
-  const loadCode = async () => {
+  useEffect(() => {
+    if (!codeModalVisible) return;
     setIsLoading(true);
     try {
-      if (isWorkflowMode && workflowSteps.length > 0) {
-        const allCode = workflowSteps
-          .filter(s => s.status === 'success' && s.result)
-          .map(s => {
+      const steps = record?.steps ?? [];
+      const successSteps = steps.filter(
+        (s) => (s.status === 'success' || s.status === 'warning') && s.result
+      );
+      if (successSteps.length > 0) {
+        const allCode = successSteps
+          .map((s) => {
             const stepCode = (s.result as any)?.reproducible_code;
             const header = `# ========================================\n# 步骤 ${s.step_number}: ${s.tool_name}\n# ========================================\n`;
-            return header + (stepCode || `# 该步骤暂无可用代码`);
+            return header + (stepCode || '# 该步骤暂无可用代码');
           })
           .join('\n\n');
-        setCode(allCode || '# 暂无可用代码\n# 请先执行分析');
-      } else {
-        const result = await downloadCode();
-        const text = await result.blob.text();
-        setCode(text);
-      }
-    } catch (error) {
-      if (executionResult?.reproducibleCode) {
-        setCode(executionResult.reproducibleCode);
+        setCode(allCode);
       } else {
         setCode('# 暂无可用代码\n# 请先执行分析');
       }
     } finally {
       setIsLoading(false);
     }
-  };
+  }, [codeModalVisible, record]);
 
   if (!codeModalVisible) return null;
 
-  const handleClose = () => {
-    setCodeModalVisible(false);
+  const handleClose = () => setCodeModalVisible(false);
+
+  const generateFilename = () => {
+    const now = new Date();
+    const pad = (n: number) => n.toString().padStart(2, '0');
+    const ts = `${now.getFullYear()}${pad(now.getMonth() + 1)}${pad(now.getDate())}_${pad(now.getHours())}${pad(now.getMinutes())}${pad(now.getSeconds())}`;
+    const title = (record?.plan?.title || 'analysis')
+      .replace(/[^a-zA-Z0-9\u4e00-\u9fa5_-]/g, '_')
+      .slice(0, 30);
+    return `SSA_${title}_${ts}.R`;
   };
 
-  const handleDownload = async () => {
+  const handleDownload = () => {
     try {
-      if (isWorkflowMode && code) {
-        const blob = new Blob([code], { type: 'text/plain' });
-        const url = URL.createObjectURL(blob);
-        const a = document.createElement('a');
-        a.href = url;
-        a.download = 'workflow_analysis.R';
-        a.click();
-        URL.revokeObjectURL(url);
-        addToast('R 脚本已下载', 'success');
-        handleClose();
-      } else {
-        const result = await downloadCode();
-        const url = URL.createObjectURL(result.blob);
-        const a = document.createElement('a');
-        a.href = url;
-        a.download = result.filename;
-        a.click();
-        URL.revokeObjectURL(url);
-        addToast('R 脚本已下载', 'success');
-        handleClose();
-      }
-    } catch (error) {
+      const blob = new Blob([code], { type: 'text/plain' });
+      const url = URL.createObjectURL(blob);
+      const a = document.createElement('a');
+      a.href = url;
+      a.download = generateFilename();
+      a.click();
+      URL.revokeObjectURL(url);
+      addToast('R 脚本已下载', 'success');
+      handleClose();
+    } catch {
       addToast('下载失败', 'error');
     }
   };
@@ -101,7 +95,7 @@ export const SSACodeModal: React.FC = () => {
             <X size={16} />
           </button>
         </header>
-        
+
         <div className="code-modal-body">
           {isLoading ? (
             <div className="code-loading">