feat: 完成管理员密码登录修复和项目清理

- 修复BCryptPasswordEncoder密码验证问题
- 实现密码设置提示弹窗功能（仅对无密码用户显示一次）
- 优化修改密码逻辑和验证流程
- 更新Welcome页面背景样式
- 清理临时SQL文件和测试代码
- 移动数据库备份文件到database/backups目录
- 删除不必要的MD文档和临时文件

demo/deploy_baota/frontend/static/Payments-2be3ab12.css

@@ -0,0 +1 @@
+.payments[data-v-a25db079]{max-width:1200px;margin:0 auto}.page-header[data-v-a25db079]{margin-bottom:20px}.page-header h2[data-v-a25db079]{margin:0;color:#303133;display:flex;align-items:center;gap:8px}.filter-card[data-v-a25db079],.payments-card[data-v-a25db079]{margin-bottom:20px}.order-link[data-v-a25db079]{color:#409eff;text-decoration:none;font-weight:500}.order-link[data-v-a25db079]:hover{text-decoration:underline}.amount[data-v-a25db079]{font-weight:600;color:#e6a23c}.description[data-v-a25db079]{color:#606266}.pagination-container[data-v-a25db079]{display:flex;justify-content:center;margin-top:20px}.payment-description[data-v-a25db079]{margin-top:20px}.payment-description h4[data-v-a25db079]{margin-bottom:12px;color:#303133}.payment-description p[data-v-a25db079]{color:#606266;line-height:1.6}.subscription-info[data-v-a25db079]{text-align:center}.subscription-info h3[data-v-a25db079]{color:#409eff;margin-bottom:.5rem}.subscription-info .price[data-v-a25db079]{font-size:2rem;font-weight:700;color:#f56c6c;margin:1rem 0}.subscription-info .description[data-v-a25db079]{color:#666;margin-bottom:1rem}.subscription-info .benefits[data-v-a25db079]{text-align:left;margin:1rem 0}.subscription-info .benefits h4[data-v-a25db079]{color:#333;margin-bottom:.5rem}.subscription-info .benefits ul[data-v-a25db079]{list-style:none;padding:0}.subscription-info .benefits li[data-v-a25db079]{padding:.25rem 0;color:#666}.subscription-info .benefits li[data-v-a25db079]:before{content:"✓ ";color:#67c23a;font-weight:700}.subscription-info .points-info[data-v-a25db079]{margin-top:1rem}.subscription-info .payment-method[data-v-a25db079]{margin-top:1.5rem;padding-top:1rem;border-top:1px solid #e4e7ed}.subscription-info .payment-method h4[data-v-a25db079]{color:#333;margin-bottom:.5rem}.subscription-info .converted-price[data-v-a25db079]{margin-top:.5rem;padding:.5rem;background-color:#f0f9ff;border-radius:4px;border:1px solid #b3d8ff}.subscription-info .price-display[data-v-a25db079]{font-size:1.2rem;font-weight:700;color:#409eff}