feat: integrate dodo brand logo

frontend/src/App.vue

@@ -1303,7 +1303,7 @@ onUnmounted(() => {
   <div v-if="!authReady" class="center"><span class="loader" />正在打开 dodo…</div>
   <div v-else-if="!authenticated" class="auth-shell">
     <section class="auth-card">
-      <div class="brand">do<span>do</span></div><p>{{ initialized ? '欢迎回来，继续把生活理顺。' : '创建你的 dodo' }}</p>
+      <div class="brand brand-lockup"><img class="brand-logo" src="/dodo-logo.svg" alt=""><span class="brand-wordmark">dodo</span></div><p>{{ initialized ? '欢迎回来，继续把生活理顺。' : '创建你的 dodo' }}</p>
       <label>用户名<input v-model="username" autocomplete="username" placeholder="你的用户名"></label>
       <label>密码<input v-model="password" type="password" autocomplete="current-password" placeholder="至少 12 位" @keyup.enter="submitAuth"></label>
       <button class="primary" @click="submitAuth">{{ initialized ? '登录' : '开始使用' }}</button>
@@ -1313,7 +1313,7 @@ onUnmounted(() => {
   <div v-else class="shell" :class="{ 'sidebar-collapsed': sidebarCollapsed, 'detail-open': Boolean(selectedTask), 'mobile-sidebar-open': mobileSidebar }">
     <div v-if="mobileSidebar || mobileDetail" class="scrim" @click="mobileSidebar=false;mobileDetail=false" />
     <aside class="sidebar" :class="{ open: mobileSidebar }" @keydown.esc="sidebarCreateOpen=false;closeArchivedListAction();closeSidebarAction()">
-      <div class="brand-row"><div class="brand small">do<span>do</span></div><button class="icon mobile-only" aria-label="关闭菜单" @click="mobileSidebar=false"><X /></button></div>
+      <div class="brand-row"><div class="brand small brand-lockup"><img class="brand-logo" src="/dodo-logo.svg" alt=""><span class="brand-wordmark">dodo</span></div><button class="icon mobile-only" aria-label="关闭菜单" @click="mobileSidebar=false"><X /></button></div>
       <nav class="primary-nav">
         <button :class="{ active: activeView==='today' }" @click="switchView('today')"><ListTodo />今天</button>
         <button :class="{ active: activeView==='tasks' && lists.find(l=>l.id===activeList)?.is_inbox }" @click="switchView('tasks', lists.find(l=>l.is_inbox)?.id)"><Inbox />收集箱</button>