fix(user): move avatar upload to hover overlay

assets/css/routes/profile/layout.css

@@ -136,24 +136,76 @@
 }
 
 .uc-header__avatar {
+  position: relative;
   flex-shrink: 0;
+  width: 140px;
+  height: 140px;
+  border-radius: 6px;
 }
 
 /* 对齐 zibll: 140px, 6px 圆角 */
 .uc-header__avatar img {
-  width: 140px;
-  height: 140px;
-  border-radius: 6px;
+  display: block;
+  box-sizing: border-box;
+  width: 100%;
+  height: 100%;
+  border-radius: inherit;
   border: 4px solid var(--surface-1);
   box-shadow: 0 4px 12px rgba(0,0,0,0.12);
   object-fit: cover;
   transition: transform 0.2s ease;
 }
 
-.uc-header__avatar img:hover {
+.uc-header__avatar-upload {
+  position: absolute;
+  inset: 0;
+  z-index: 1;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: 7px;
+  width: 100%;
+  padding: 0;
+  border: 0;
+  border-radius: inherit;
+  background: rgba(0, 0, 0, 0.52);
+  color: #fff;
+  font-size: 13px;
+  font-weight: 600;
+  line-height: 1;
+  cursor: pointer;
+  opacity: 0;
+  visibility: hidden;
+  transition: opacity 0.2s ease, visibility 0.2s ease;
+}
+
+.uc-header__avatar-upload i {
+  font-size: 22px;
+}
+
+.uc-header__avatar:hover .uc-header__avatar-upload,
+.uc-header__avatar:focus-within .uc-header__avatar-upload {
+  opacity: 1;
+  visibility: visible;
+}
+
+.uc-header__avatar:hover img,
+.uc-header__avatar:focus-within img {
   transform: scale(1.03);
 }
 
+.uc-header__avatar-upload:focus-visible {
+  outline: 2px solid #fff;
+  outline-offset: -5px;
+}
+
+.uc-header__avatar-upload:disabled {
+  cursor: wait;
+  opacity: 1;
+  visibility: visible;
+}
+
 .uc-header__info {
   flex: 1;
   min-width: 0;
@@ -289,11 +341,25 @@
     gap: 14px;
   }
 
-  .uc-header__avatar img {
+  .uc-header__avatar {
     width: 90px;
     height: 90px;
   }
 
+  .uc-header__avatar img {
+    width: 100%;
+    height: 100%;
+  }
+
+  .uc-header__avatar-upload {
+    gap: 5px;
+    font-size: 12px;
+  }
+
+  .uc-header__avatar-upload i {
+    font-size: 18px;
+  }
+
   .uc-header__name {
     font-size: 1.15rem;
   }