fix(h5): 修复H5 SSE流完成信号兼容和页面onShow时序

- sendHttpStream 兼容 data.event === 'done' 和嵌套 data.data 格式
- index.vue onShow 用  确保 ref 就绪后加载历史
- 组件 mounted 兜底调用 loadHistoryIfNeeded
- 历史消息映射添加 type:'text'，兼容 msg.content 字段
- 去掉所有有帮助/没帮助按钮

common/js/ai-service.js

@@ -344,15 +344,21 @@ export default {
               if (jsonStr && jsonStr !== '[DONE]') {
                 const data = JSON.parse(jsonStr);
                 if (data.event === 'message') {
-                  const text = data.answer || data.text || '';
+                  var text = data.answer || data.text || '';
+                  // 兼容嵌套 data.data 格式
+                  if (!text && data.data) {
+                    text = data.data.content || data.data.answer || '';
+                  }
                   content += text;
                   if (onChunk) onChunk(text);
                 }
-                if (data.conversation_id) {
-                  conversationId = data.conversation_id;
+                // 兼容两种层级：conversation_id 可能在顶层或 data.data 中
+                var cid = data.conversation_id || (data.data && data.data.conversation_id) || '';
+                if (cid) {
+                  conversationId = cid;
                 }
-                if (data.event === 'message_end') {
-                  // 可提前结束
+                if (data.event === 'message_end' || data.event === 'done') {
+                  console.log('[AI SSE] 收到完成信号:', data.event, 'conversationId:', cid);
                 }
               }
             } catch (e) {
@@ -369,12 +375,16 @@ export default {
           if (jsonStr) {
             const data = JSON.parse(jsonStr);
             if (data.event === 'message') {
-              const text = data.answer || '';
+              var text = data.answer || data.text || '';
+              if (!text && data.data) {
+                text = data.data.content || data.data.answer || '';
+              }
               content += text;
               if (onChunk) onChunk(text);
             }
-            if (data.conversation_id) {
-              conversationId = data.conversation_id;
+            var cid = data.conversation_id || (data.data && data.data.conversation_id) || '';
+            if (cid) {
+              conversationId = cid;
             }
           }
         } catch (e) {
@@ -382,6 +392,7 @@ export default {
         }
       }
 
+      console.log('[AI SSE] 流完成, conversationId:', conversationId, 'content长度:', content.length);
       if (onComplete) {
         onComplete({ content, conversation_id: conversationId });
       }