fix: improve email notification summary generation

- Refactor the way the email summary is constructed
- Ensure that the summary is set correctly based on the presence of stats
- Update the log message to reflect the changes in summary content

This change improves the clarity of the email notifications by
ensuring that the summary is generated correctly based on the
availability of synchronization statistics. It also enhances the
readability of the logs by updating the labels for the log
sections.

main.sh

@@ -55,12 +55,7 @@ main() {
 
     # 准备邮件内容
     notice_subject="GitHub 同步$([ $mirror_exit_code -eq 0 ] && echo "成功" || echo "失败") - $(date '+%Y-%m-%d')"
-    notice_content="GitHub to Gitea 同步报告
-
-运行时间: $(date '+%Y-%m-%d %H:%M:%S')
-
-详细日志:
-$(cat "${LOG_FILE}")"
+    summary=""
 
     if [ -f "$STATS_FILE" ]; then
         stats=$(cat "$STATS_FILE")
@@ -85,18 +80,21 @@ $(echo "$stats" | jq -r '.details.failed_repos[]' | sed 's/^/- /')
 
 成功的仓库：
 $(echo "$stats" | jq -r '.details.success_repos[]' | sed 's/^/- /')
-
-详细日志 (最后 50 行):
-$(tail -n 50 "$LOG_FILE")
-
-详细日志:
-$(cat "$LOG_FILE")
 "
 
     else
         summary="无法获取同步统计信息"
     fi
 
+    notice_content="$summary
+
+详细日志 (最后 50 行):
+$(tail -n 50 "$LOG_FILE")
+
+全部日志:
+$(cat "$LOG_FILE")
+"
+
     # 如果启用了邮件通知，调用 mail.sh
     if [ "$ENABLE_MAIL" = "true" ]; then
         bash "$SCRIPT_DIR/mail.sh" \