feat(uikit): 引入明缘主题色板与通用组件

uikit/src/main/ets/components/Avatar.ets

@@ -0,0 +1,23 @@
+import { AppColor } from '../theme/Theme';
+
+/**
+ * 首字母圆形头像：金色底白字。
+ */
+@ComponentV2
+export struct Avatar {
+  @Param name: string = '';
+  @Param diameter: number = 40;
+
+  build() {
+    Stack({ alignContent: Alignment.Center }) {
+      Text(this.name.length > 0 ? this.name.charAt(0) : '明')
+        .fontSize(this.diameter * 0.42)
+        .fontWeight(FontWeight.Bold)
+        .fontColor(AppColor.white)
+    }
+    .width(this.diameter)
+    .height(this.diameter)
+    .borderRadius(this.diameter / 2)
+    .backgroundColor(AppColor.gold)
+  }
+}