fix: 修复 PR 生成页 INLINECODE 显示及复制 Markdown 失败问题

- 改进 LLM 提示词，明确要求用反引号包裹代码引用，避免输出 INLINECODE 占位符
- 后端新增 fixInlineCode 后处理，将残留 INLINECODE 占位符转为反引号代码
- 前端在 done 回调中从结构化字段组装完整 markdown 文本，修复复制按钮复制空内容
- 复制按钮增加空内容检查和错误提示
- Markdown 预览区域初始隐藏，生成完成后自动显示

services/generate.go

@@ -4,6 +4,7 @@ import (
 	"database/sql"
 	"encoding/json"
 	"fmt"
+	"regexp"
 	"strings"
 
 	"github.com/go-git/go-git/v5/plumbing"
@@ -111,7 +112,11 @@ func GeneratePR(db *sql.DB, repoPath, base, head string, userID int64, callback
   "summary": "一段话概述变更内容",
   "details": "详细的变更说明，按模块分组，使用 Markdown 格式",
   "impact": "影响范围说明"
-}`, commitStr, diff)
+}
+
+重要格式要求：
+- details 字段中引用文件名、函数名、变量名等代码标识时，必须用反引号包裹，例如：`+"`services/generate.go`"+`, `+"`GeneratePR()`"+`
+- 直接写出实际的代码名称，不要用任何占位符替代`, commitStr, diff)
 
 	messages := []goopenai.ChatCompletionMessage{
 		{Role: goopenai.ChatMessageRoleUser, Content: prompt},
@@ -130,6 +135,9 @@ func GeneratePR(db *sql.DB, repoPath, base, head string, userID int64, callback
 		return nil, fmt.Errorf("parse PR description: %w (raw: %s)", err, truncateString(fullResponse, 200))
 	}
 
+	// Post-process: convert INLINECODE placeholders back to backtick-enclosed code
+	pr.Details = fixInlineCode(pr.Details)
+
 	// Send structured events
 	if callback != nil {
 		callback("title", map[string]interface{}{"content": pr.Title})
@@ -143,6 +151,16 @@ func GeneratePR(db *sql.DB, repoPath, base, head string, userID int64, callback
 	return &pr, nil
 }
 
+// fixInlineCode converts LLM-generated INLINECODE placeholders back to backtick-enclosed inline code.
+// Some LLMs output INLINECODE0, INLINECODE1, etc. instead of `code` in JSON string values.
+// This wraps them in backticks so the frontend markdown renderer displays them as inline code.
+func fixInlineCode(text string) string {
+	re := regexp.MustCompile(`(?i)INLINECODE[_]?(\d+)`)
+	return re.ReplaceAllStringFunc(text, func(match string) string {
+		return "`" + match + "`"
+	})
+}
+
 func truncateString(s string, maxLen int) string {
 	if len(s) <= maxLen {
 		return s