fix(mine): replace static avatar with dynamic dicebear image

mini-program/src/pages/main/MineView.vue

@@ -12,8 +12,7 @@
     <view class="avatar-stage">
       <view class="avatar-glow"></view>
       <view class="avatar-circle">
-        <view class="person-head"></view>
-        <view class="person-body"></view>
+        <image class="avatar-img" :src="avatarUrl" mode="aspectFill" />
       </view>
       <view class="verify-badge">✓</view>
     </view>
@@ -68,6 +67,11 @@ import { useAppStore } from '../../stores/app.js'
 const store = useAppStore()
 const profile = computed(() => store.userProfile || store.registrationData || {})
 
+const avatarUrl = computed(() => {
+  const seed = profile.value.nickname || 'user'
+  return `https://api.dicebear.com/7.x/avataaars/svg?seed=${encodeURIComponent(seed)}&backgroundColor=b982ff`
+})
+
 const displayName = computed(() => profile.value.nickname || '张义明')
 
 const metaLine = computed(() => {
@@ -395,4 +399,10 @@ const terminateLifeHarmony = () => {
   font-size: 22rpx;
   letter-spacing: 8rpx;
 }
+
+.avatar-img {
+  width: 100%;
+  height: 100%;
+  border-radius: 50%;
+}
 </style>