feat: 颜色组件透明度属性

src/views/components/PenProps.vue

@@ -391,6 +391,7 @@
                         format="CSS"
                         :color-modes="['monochrome']"
                         :show-primary-color-preview="false"
+                        enable-alpha
                         v-model="data.pen.background"
                         @change="changeValue('background')"
                       />

src/views/components/PensProps.vue

@@ -339,6 +339,7 @@
                       <t-color-picker
                         class="w-full"
                         format="CSS"
+                        :enable-alpha="true"
                         :color-modes="['monochrome']"
                         :show-primary-color-preview="false"
                         v-model="data.background"