refactor: 升级Vue SFC深度选择器语法为::v-deep

本次提交将项目中所有使用`::deep`的CSS深度选择器统一替换为Vue 3官方推荐的`::v-deep`语法，修复了旧版语法在新版本Vue生态中的兼容性问题，同时修正了部分组件的响应式表单定义方式，将`reactive`配合`Object.assign`的写法调整为更符合Vue 3组合式API规范的`ref`响应式状态写法，整体优化了代码的可维护性和兼容性。

frontend/web/src/views/module_system/auth/login/components/LoginAuthLinkRow.vue

@@ -22,8 +22,8 @@ defineEmits<{ link: [] }>();
 
 <style scoped lang="scss">
 .login-auth-link-row {
-  ::deep(.el-link),
-  ::deep(.el-link__inner) {
+  ::v-deep(.el-link),
+  ::v-deep(.el-link__inner) {
     line-height: inherit;
   }
 }

frontend/web/src/views/module_system/auth/login/components/LoginMobilePanel.vue

@@ -246,11 +246,11 @@ html.dark {
 
 /* EP 全局规则：相邻 .el-button { margin-left: 12px }，纵向叠放时仍会命中，导致第二颗按钮横向错位 */
 .login-mobile-actions {
-  ::deep(.el-button + .el-button) {
+  ::v-deep(.el-button + .el-button) {
     margin-left: 0 !important;
   }
 
-  ::deep(.el-button) {
+  ::v-deep(.el-button) {
     box-sizing: border-box;
     width: 100%;
     min-width: 0;

frontend/web/src/views/module_system/auth/login/components/LoginQrPanel.vue

@@ -78,7 +78,7 @@ const qrPayload = computed(() => {
 
 /* EP：相邻按钮横向间距；单列返回按钮无需处理 */
 .login-mobile-actions {
-  ::deep(.el-button) {
+  ::v-deep(.el-button) {
     box-sizing: border-box;
     width: 100%;
     min-width: 0;

frontend/web/src/views/module_system/auth/login/index.vue

@@ -661,68 +661,68 @@ async function submitForget() {
 
 <style lang="scss" scoped>
 .login-page-panel {
-  ::deep(.btn) {
+  ::v-deep(.btn) {
     border-radius: 8px;
   }
 }
 
 html.dark .login-page-panel {
-  ::deep(.text-g-800) {
+  ::v-deep(.text-g-800) {
     color: rgb(255 255 255 / 78%) !important;
   }
 }
 
 /* 副标题与表单块间距（login-page-form 在子组件内，须 :deep） */
-::deep(.login-page-form) {
+::v-deep(.login-page-form) {
   margin-top: 1rem;
 }
 
-::deep(.login-page-form .el-form-item) {
+::v-deep(.login-page-form .el-form-item) {
   margin-bottom: 1.1rem;
 }
 
-::deep(.el-select__wrapper) {
+::v-deep(.el-select__wrapper) {
   min-height: 42px !important;
 }
 
 /* 仅账号登录底部「手机号 / 扫码」双列按钮需要 42px；手机号登录页的返回钮与主按钮同为 h-11，勿全局压高度 */
-::deep(.login-secondary-actions .login-secondary-btn) {
+::v-deep(.login-secondary-actions .login-secondary-btn) {
   height: 42px;
   border-radius: 8px;
 }
 
 html.dark {
-  ::deep(.login-page-form .el-input__wrapper) {
+  ::v-deep(.login-page-form .el-input__wrapper) {
     background-color: rgb(255 255 255 / 6%) !important;
     box-shadow: 0 0 0 1px rgb(255 255 255 / 10%) inset !important;
   }
 
-  ::deep(.login-page-form .el-input__inner) {
+  ::v-deep(.login-page-form .el-input__inner) {
     color: rgb(255 255 255 / 92%);
   }
 
-  ::deep(.login-page-form .el-input__inner::placeholder) {
+  ::v-deep(.login-page-form .el-input__inner::placeholder) {
     color: rgb(255 255 255 / 35%);
   }
 
-  ::deep(.login-page-form .el-select .el-select__wrapper) {
+  ::v-deep(.login-page-form .el-select .el-select__wrapper) {
     background-color: rgb(255 255 255 / 6%) !important;
     box-shadow: 0 0 0 1px rgb(255 255 255 / 10%) inset !important;
   }
 
-  ::deep(.login-page-form .el-select__placeholder) {
+  ::v-deep(.login-page-form .el-select__placeholder) {
     color: rgb(255 255 255 / 40%);
   }
 
-  ::deep(.login-page-form .el-select__selected-item) {
+  ::v-deep(.login-page-form .el-select__selected-item) {
     color: rgb(255 255 255 / 92%);
   }
 
-  ::deep(.login-remember .el-checkbox__label) {
+  ::v-deep(.login-remember .el-checkbox__label) {
     color: rgb(255 255 255 / 65%);
   }
 
-  ::deep(.login-secondary-btn) {
+  ::v-deep(.login-secondary-btn) {
     color: rgb(255 255 255 / 85%) !important;
     background: transparent !important;
     border-color: rgb(255 255 255 / 22%) !important;
@@ -735,7 +735,7 @@ html.dark {
     }
   }
 
-  ::deep(.login-secondary-actions .login-secondary-btn) {
+  ::v-deep(.login-secondary-actions .login-secondary-btn) {
     height: 42px;
   }
 }