fix: 头像上传后前端不显示真头像 (row29 续)

真因:上传成功且 setUser 写入了 avatar_url,但前端任何头像位置都没渲染 avatar_url,
只显示姓氏首字占位 → 看着像「没更新」。根因:User 类型里压根没暴露 avatar_url 字段。

修:User 类型补 avatar_url;侧栏 .user、账户菜单 .shell-account-head、设置页 av-big
三处头像改为「有 avatar_url 显 <img>,空则回退首字」;.av/.av-big 加 overflow:hidden + img 铺满规则。
后端上传 200 + 直链公读已实测正常,此为纯前端显示修复。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/frontend/src/components/app-shell.tsx

@@ -167,7 +167,7 @@ function AccountMenu({ anchorRect, onClose, navigate, logout, user, team, canMan
       style={{ left: pos.left, top: pos.top }}
     >
       <div className="shell-account-head">
-        <span className="av">{avatar}</span>
+        <span className="av">{user.avatar_url ? <img src={user.avatar_url} alt="头像" /> : avatar}</span>
         <span>
           <span className="nm">{team?.name || user.username}</span>
           <span className="mail">{user.username}</span>
@@ -374,7 +374,7 @@ export function Sidebar({ page, navigate, user, team, canManageBilling = true, p
           onClick={toggleAccountMenu}
           onKeyDown={(event) => { if (event.key === "Enter" || event.key === " ") { event.preventDefault(); toggleAccountMenu(event as unknown as ReactMouseEvent<HTMLElement>); } }}
         >
-          <div className="av">{avatar}</div>
+          <div className="av">{user.avatar_url ? <img src={user.avatar_url} alt="头像" /> : avatar}</div>
           <div className="em">{team?.name || user.username}</div>
         </div>
       </div>