出题表单：修复 SQL 题崩溃并隐藏流程图区域

流程图区域的"AI 生成"按钮读取 problem.answers 里 language==='Python3' 的
第一项 .code，SQL 题（languages=["SQL"]）没有 Python3 答案，[0] 为
undefined，导致模板抛 TypeError 崩溃整个出题页。

流程图功能本身依赖 Python 答案生成 Mermaid 代码，对 SQL 题没有意义，
和已隐藏的"代码规则检查"一样直接整块隐藏（切到 SQL 时顺带重置
allow_flowchart/show_flowchart，避免脏数据）。顺手给禁用态判断加了
可选链，修掉未选 Python3 时同样会崩的潜在问题（如仅选 C/C++ 的题目）。

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/admin/problem/detail.vue

@@ -202,6 +202,9 @@ watch(
       if (problem.value.ast_rules) {
         problem.value.ast_rules = null
       }
+      // 流程图依赖 Python 答案生成，对 SQL 没有意义
+      problem.value.allow_flowchart = false
+      problem.value.show_flowchart = false
     } else if (problem.value.sql_config) {
       problem.value.sql_config = null
     }
@@ -844,48 +847,50 @@ watch(
     />
   </n-modal>
 
-  <n-divider />
+  <template v-if="!isSQLProblem">
+    <n-divider />
 
-  <h2 class="title">流程图区域</h2>
+    <h2 class="title">流程图区域</h2>
 
-  <!-- 流程图相关设置 -->
+    <!-- 流程图相关设置 -->
-  <n-form inline label-placement="left" :show-feedback="false">
+    <n-form inline label-placement="left" :show-feedback="false">
-    <n-form-item label="根据上面的【Python答案】智能生成 Mermaid 代码">
+      <n-form-item label="根据上面的【Python答案】智能生成 Mermaid 代码">
-      <n-button
+        <n-button
-        type="primary"
+          type="primary"
-        size="small"
+          size="small"
-        :disabled="
+          :disabled="
-          !problem.answers.filter((a) => a.language === 'Python3')[0].code
+            !problem.answers.filter((a) => a.language === 'Python3')[0]?.code
-            .length
+              .length
-        "
+          "
-        :loading="isAIGenerating"
+          :loading="isAIGenerating"
-        @click="generateMermaid"
+          @click="generateMermaid"
-      >
+        >
-        AI 生成
+          AI 生成
-      </n-button>
+        </n-button>
-    </n-form-item>
+      </n-form-item>
-    <n-form-item label="允许提交流程图">
+      <n-form-item label="允许提交流程图">
-      <n-switch v-model:value="problem.allow_flowchart" />
+        <n-switch v-model:value="problem.allow_flowchart" />
-    </n-form-item>
+      </n-form-item>
-    <n-form-item label="显示标准流程图">
+      <n-form-item label="显示标准流程图">
-      <n-switch v-model:value="problem.show_flowchart" />
+        <n-switch v-model:value="problem.show_flowchart" />
-    </n-form-item>
+      </n-form-item>
-  </n-form>
+    </n-form>
 
-  <n-form>
+    <n-form>
-    <n-form-item>
+      <n-form-item>
-      <MermaidEditor
+        <MermaidEditor
-        v-model="problem.mermaid_code"
+          v-model="problem.mermaid_code"
-        @render-success="onMermaidRenderSuccess"
+          @render-success="onMermaidRenderSuccess"
-      />
+        />
-    </n-form-item>
+      </n-form-item>
-    <n-form-item label="流程图提示信息（选填）">
+      <n-form-item label="流程图提示信息（选填）">
-      <n-input
+        <n-input
-        v-model:value="problem.flowchart_hint"
+          v-model:value="problem.flowchart_hint"
-        placeholder="请输入流程图相关的提示信息，帮助学生理解题目要求"
+          placeholder="请输入流程图相关的提示信息，帮助学生理解题目要求"
-      />
+        />
-    </n-form-item>
+      </n-form-item>
-  </n-form>
+    </n-form>
+  </template>
   <n-flex style="margin-bottom: 120px" align="center" justify="end">
     <n-button type="primary" @click="submit">提交</n-button>
   </n-flex>