fix(authentication): improve name editor layout and add focus border

1. Replace fixed maxWidth with fillWidth for adaptive input width
2. Set input height to 30px with 5px vertical margins (matches
   itemDelegate height)
3. Remove redundant spacer item before edit button
4. Show blue focus border only during editing (focus + !readOnly)
5. Align with Bluetooth rename UI behavior

1. 将输入框从固定宽度改为 fillWidth 自适应填充
2. 设置输入框高度为30px，上下5px边距，保持行高40px
3. 移除编辑按钮前冗余的占位元素
4. 蓝色焦点边框仅在编辑状态（聚焦且非只读）时显示
5. 与蓝牙重命名界面的交互表现保持一致

Log: 优化认证模块用户名输入框布局与焦点边框样式
PMS: BUG-365807
Influence: 编辑用户名时输入框自适应宽度、高度匹配列表项规范，
蓝色焦点边框仅在编辑模式下显示，与蓝牙重命名体验对齐

Author: Ivy233

src/plugin-authentication/qml/AuthenticationMain.qml

@@ -146,9 +146,11 @@ DccObject {
                             id: nameEditor
                             property int maxLength: 15
                             Layout.leftMargin: 10
-                            Layout.minimumWidth: contentWidth + leftPadding + rightPadding
-                            Layout.maximumWidth: 200
-                            implicitHeight: DS.Style.itemDelegate.height
+                            Layout.rightMargin: 10
+                            Layout.fillWidth: true
+                            implicitHeight: 30
+                            Layout.topMargin: 5
+                            Layout.bottomMargin: 5
                             horizontalAlignment: TextInput.AlignLeft
                             text: modelData
                             readOnly: true
@@ -157,7 +159,7 @@ DccObject {
                             background: D.EditPanel {
                                 id: nameEditPanel
                                 control: nameEditor
-                                showBorder: false
+                                showBorder: nameEditor.activeFocus && !nameEditor.readOnly
                                 alertDuration: 3000
                                 backgroundColor: D.Palette {
                                     normal: Qt.rgba(1, 1, 1, 0)
@@ -255,9 +257,6 @@ DccObject {
                             }
                         }
 
-                        Item {
-                            Layout.fillWidth: true
-                        }
                         D.ActionButton {
                             id: editButton
                             visible: hoverHandler.hovered || layout.showActions