后台账号体系改造：接入t_admin_数据库账号与前端改密

变更项：
1. 新增 db/admin_account_db.py，提供 t_admin_accounts 表初始化、PBKDF2口令哈希、登录校验、登录信息回写与密码更新能力。
2. DashboardServer 启动时接入账号数据层，自动建表并把旧配置默认账号迁移为数据库账号种子。
3. 重构 auth 登录逻辑：优先走数据库账号鉴权，保留旧配置账号回退；新增 /api/auth/change_password 接口支持在线修改密码。
4. base.html 增加顶部修改密码入口与弹窗表单，前端可直接提交旧密码与新密码完成改密。
5. login.html 增强小屏适配：允许纵向滚动、768以下隐藏展示侧栏并优化输入区间距与字号，修复移动端登录体验。
6. 新增迁移脚本 db/scripts/migrations/20260423_add_admin_account_table.sql，便于独立数据库升级。

admin/dashboard/templates/base.html

@@ -224,6 +224,18 @@
             transition: all .18s ease !important;
         }
 
+        .account-btn {
+            color: var(--text-soft) !important;
+            padding: 10px 14px !important;
+            border-radius: 999px !important;
+            transition: all .18s ease !important;
+        }
+
+        .account-btn:hover {
+            color: var(--primary) !important;
+            background: var(--primary-soft) !important;
+        }
+
         .logout-btn:hover {
             color: var(--primary) !important;
             background: var(--primary-soft) !important;
@@ -699,6 +711,13 @@
                 display: none;
             }
         }
+
+        .password-dialog-tip {
+            margin-top: 8px;
+            color: var(--text-faint);
+            font-size: 12px;
+            line-height: 1.7;
+        }
     </style>
 
     <link rel="stylesheet" href="/static/css/element-ui/theme-chalk/index.min.css">
@@ -741,7 +760,10 @@
                 </div>
                 <div class="user-pill">
                     <span class="user-dot"></span>
-                    <span>管理员已登录</span>
+                    <span>{{ session.get('username', '管理员') }} 已登录</span>
+                </div>
+                <el-button type="text" class="account-btn" @click="openPasswordDialog">
+                    <i class="el-icon-lock"></i> 修改密码
                 </div>
                 <el-button type="text" class="logout-btn" @click="logout">
                     <i class="el-icon-switch-button"></i> 退出
@@ -785,6 +807,35 @@
                 </div>
             </main>
         </div>
+
+        <el-dialog
+            title="修改后台登录密码"
+            :visible.sync="passwordDialogVisible"
+            width="460px"
+            :close-on-click-modal="false">
+            <el-form
+                ref="passwordFormRef"
+                :model="passwordForm"
+                :rules="passwordRules"
+                label-width="96px">
+                <el-form-item label="旧密码" prop="old_password">
+                    <el-input v-model="passwordForm.old_password" type="password" show-password autocomplete="off" placeholder="请输入当前密码"></el-input>
+                </el-form-item>
+                <el-form-item label="新密码" prop="new_password">
+                    <el-input v-model="passwordForm.new_password" type="password" show-password autocomplete="off" placeholder="至少6位"></el-input>
+                </el-form-item>
+                <el-form-item label="确认新密码" prop="confirm_password">
+                    <el-input v-model="passwordForm.confirm_password" type="password" show-password autocomplete="off" placeholder="请再次输入新密码"></el-input>
+                </el-form-item>
+            </el-form>
+            <div class="password-dialog-tip">
+                提示：修改成功后将立即生效，建议使用强密码（字母、数字、符号组合）。
+            </div>
+            <span slot="footer" class="dialog-footer">
+                <el-button @click="passwordDialogVisible = false">取消</el-button>
+                <el-button type="primary" :loading="passwordSubmitting" @click="submitPasswordChange">确认修改</el-button>
+            </span>
+        </el-dialog>
     </div>
 
 <script>
@@ -870,7 +921,37 @@
                 currentView: '1',
                 timeRange: '7',
                 showTimeRangeSelector: false,
-                navGroups: NAV_GROUPS
+                navGroups: NAV_GROUPS,
+                // 账号密码修改弹窗状态。
+                passwordDialogVisible: false,
+                passwordSubmitting: false,
+                passwordForm: {
+                    old_password: '',
+                    new_password: '',
+                    confirm_password: ''
+                },
+                passwordRules: {
+                    old_password: [
+                        { required: true, message: '请输入旧密码', trigger: 'blur' }
+                    ],
+                    new_password: [
+                        { required: true, message: '请输入新密码', trigger: 'blur' },
+                        { min: 6, message: '新密码长度至少6位', trigger: 'blur' }
+                    ],
+                    confirm_password: [
+                        { required: true, message: '请再次输入新密码', trigger: 'blur' },
+                        {
+                            validator: (rule, value, callback) => {
+                                if (value !== this.passwordForm.new_password) {
+                                    callback(new Error('两次输入的新密码不一致'));
+                                    return;
+                                }
+                                callback();
+                            },
+                            trigger: 'blur'
+                        }
+                    ]
+                }
             }
         },
         computed: {
@@ -948,6 +1029,49 @@
                 }).then(() => {
                     window.location.href = '/logout';
                 });
+            },
+            openPasswordDialog() {
+                // 打开弹窗前重置表单，避免上次输入残留。
+                this.passwordDialogVisible = true;
+                this.passwordSubmitting = false;
+                this.passwordForm = {
+                    old_password: '',
+                    new_password: '',
+                    confirm_password: ''
+                };
+                this.$nextTick(() => {
+                    if (this.$refs.passwordFormRef) {
+                        this.$refs.passwordFormRef.clearValidate();
+                    }
+                });
+            },
+            submitPasswordChange() {
+                if (!this.$refs.passwordFormRef) {
+                    return;
+                }
+                this.$refs.passwordFormRef.validate((valid) => {
+                    if (!valid) {
+                        return;
+                    }
+                    this.passwordSubmitting = true;
+                    axios.post('/api/auth/change_password', this.passwordForm)
+                        .then((response) => {
+                            const data = response.data || {};
+                            if (!data.success) {
+                                this.$message.error(data.error || '修改密码失败');
+                                return;
+                            }
+                            this.$message.success(data.message || '密码修改成功');
+                            this.passwordDialogVisible = false;
+                        })
+                        .catch((error) => {
+                            const errorMsg = error?.response?.data?.error || '修改密码失败，请稍后重试';
+                            this.$message.error(errorMsg);
+                        })
+                        .finally(() => {
+                            this.passwordSubmitting = false;
+                        });
+                });
             }
         }
     };

admin/dashboard/templates/login.html

@@ -36,7 +36,8 @@
             display: flex;
             align-items: center;
             justify-content: center;
-            overflow: hidden;
+            overflow-x: hidden;
+            overflow-y: auto;
         }
         .login-shell {
             width: min(1120px, calc(100vw - 48px));
@@ -200,12 +201,53 @@
             width: 8px; height: 8px; border-radius: 50%; background: #10b981; box-shadow: 0 0 0 4px rgba(16,185,129,0.12);
         }
         @media (max-width: 960px) {
-            .login-shell { grid-template-columns: 1fr; min-height: auto; }
+            body { align-items: flex-start; padding: 18px 14px; }
+            .login-shell { grid-template-columns: 1fr; min-height: auto; width: 100%; border-radius: 24px; }
             .login-showcase { padding: 34px 28px; }
             .hero-title { font-size: 34px; }
             .showcase-metrics { grid-template-columns: 1fr; }
             .login-panel { padding: 32px 24px; }
         }
+        @media (max-width: 768px) {
+            .login-shell {
+                box-shadow: 0 16px 32px rgba(15, 23, 42, 0.12);
+                border-radius: 18px;
+                min-height: 0;
+            }
+            .login-showcase {
+                display: none;
+            }
+            .login-panel {
+                padding: 22px 16px;
+            }
+            .login-card {
+                max-width: none;
+            }
+            .panel-title {
+                font-size: 24px;
+            }
+            .panel-desc {
+                font-size: 13px;
+                margin-bottom: 18px;
+            }
+            .el-input__inner,
+            .login-button {
+                height: 44px;
+                border-radius: 12px;
+            }
+            .panel-footer {
+                flex-direction: column;
+                align-items: flex-start;
+                gap: 6px;
+            }
+        }
+        @media (max-width: 420px) {
+            body { padding: 12px; }
+            .login-shell { width: 100%; }
+            .login-panel { padding: 16px 12px; }
+            .panel-eyebrow { margin-bottom: 12px; }
+            .panel-title { font-size: 22px; }
+        }
     </style>
 </head>
 <body>