diff --git a/docs/update.md b/docs/update.md
index 86247a8..de83801 100644
--- a/docs/update.md
+++ b/docs/update.md
@@ -1,5 +1,9 @@
 # 업데이트 로그
 
+## 2026-04-01 v1.3.29
+- 책 아이콘 사용법 모달 진입점은 항상 보이는 오른쪽 사이드 하단 버튼 대신, Settings 화면에서만 왼쪽 사이드 하단의 보조 액션 버튼으로 옮겨 더 필요할 때만 찾게 되는 문맥형 진입 방식으로 정리함.
+- 인증 스토어에 초기 세션 동기화 완료 상태를 추가하고, 앱 셸·로그인 화면·프로필 화면은 세션 확인 전까지 비로그인 UI를 먼저 그리지 않도록 보강해 첫 진입 시 화면이 갑자기 로그인 상태로 뒤집히는 플래시를 줄임.
+
 ## 2026-04-01 v1.3.28
 - 책 아이콘 기반 사용법 모달은 기존의 단순 제작 흐름 안내를 넘어, 다른 사람 티어표 복사, 템플릿 업그레이드 요청, 새 템플릿 추가 요청, 즐겨찾기/내 티어표 관리까지 포함한 전체 기능 안내 허브로 확장함.
 - 사용법 모달 제목과 단계 표기를 더 넓은 개념의 `기능 안내` 기준으로 정리하고, 실제 스크린샷이 없어도 설명만으로 핵심 기능을 순서대로 이해할 수 있게 단계 문구를 전면 보강함.
diff --git a/frontend/src/App.vue b/frontend/src/App.vue
index 0904013..1eb87b0 100644
--- a/frontend/src/App.vue
+++ b/frontend/src/App.vue
@@ -31,7 +31,8 @@ const viewportWidth = ref(typeof window !== 'undefined' ? window.innerWidth : 14
 provide('rightRailOpen', rightRailOpen)
 provide('localRightRailTarget', '#local-right-rail-root')
 
-const isAdmin = computed(() => !!auth.user?.isAdmin)
+const authReady = computed(() => auth.hydrated)
+const isAdmin = computed(() => authReady.value && !!auth.user?.isAdmin)
 const isPreviewMode = computed(() => route.query.preview === '1')
 const usesLocalRightRail = computed(() => ['editEditor', 'newEditor', 'admin'].includes(String(route.name || '')))
 const isRightRailOverlay = computed(() => viewportWidth.value <= 1200)
@@ -44,7 +45,10 @@ const accountName = computed(() => {
   if (email) return email.split('@')[0] || email
   return 'Guest'
 })
-const accountEmail = computed(() => (auth.user?.email || '').trim() || '로그인 후 개인 메뉴를 사용할 수 있어요.')
+const accountEmail = computed(() => {
+  if (!authReady.value) return '계정 상태를 확인하고 있어요.'
+  return (auth.user?.email || '').trim() || '로그인 후 개인 메뉴를 사용할 수 있어요.'
+})
 const shellStyle = computed(() => ({
   '--left-rail-width': leftRailCollapsed.value ? '76px' : '248px',
   '--right-rail-width': !isRightRailOverlay.value && rightRailOpen.value ? '325px' : '0px',
@@ -56,9 +60,10 @@ const leftNavItems = computed(() => {
     { key: 'favorites', label: 'Favorites', path: '/favorites', iconSrc: iconFavorite, requiresAuth: true },
     { key: 'profile', label: 'Settings', path: '/profile', iconSrc: iconSettings, requiresAuth: true },
   ]
-  return items.filter((item) => !item.requiresAuth || auth.user)
+  return items.filter((item) => !item.requiresAuth || (authReady.value && auth.user))
 })
 const showRightRailAction = computed(() => false)
+const showSettingsGuideButton = computed(() => route.name === 'profile')
 const guideSteps = [
   {
     id: 'select-game',
@@ -123,6 +128,7 @@ const isGuideNextDisabled = computed(() => guideStepIndex.value >= guideSteps.le
 const showGameHubViewToggle = computed(() => route.name === 'gameHub')
 const gameHubViewMode = computed(() => (route.query.view === 'list' ? 'list' : 'grid'))
 const leftBottomPrimaryAction = computed(() => {
+  if (!authReady.value) return null
   if (route.name === 'home' && auth.user) {
     return { label: '커스텀 티어표 만들기', to: '/editor/freeform/new' }
   }
@@ -401,7 +407,7 @@ function submitGlobalSearch() {
 
         <div class="leftRail__body">
         <div class="leftRail__content">
-        <div v-if="auth.user" class="appUserCard">
+        <div v-if="authReady && auth.user" class="appUserCard">
           <div class="appUserCard__button">
             <img v-if="avatarUrl" :src="avatarUrl" class="appUserCard__avatar" alt="avatar" />
             <div v-else class="appUserCard__avatar appUserCard__avatar--fallback">{{ accountName[0]?.toUpperCase() || 'U' }}</div>
@@ -442,8 +448,12 @@ function submitGlobalSearch() {
         </div>
         <div class="leftRail__bottom">
           <RouterLink v-if="leftBottomPrimaryAction" :to="leftBottomPrimaryAction.to" class="adminButton">{{ leftBottomPrimaryAction.label }}</RouterLink>
-          <RouterLink v-if="isAdmin" to="/admin" class="adminButton">관리자 메뉴</RouterLink>
-          <RouterLink v-else-if="!auth.user" to="/login" class="adminButton">로그인</RouterLink>
+          <button v-if="showSettingsGuideButton" class="adminButton adminButton--icon" type="button" @click="openGuideModal()">
+            <SvgIcon :src="iconMenuBook" :size="18" class="adminButton__icon" />
+            <span>가이드 보기</span>
+          </button>
+          <RouterLink v-if="authReady && isAdmin" to="/admin" class="adminButton">관리자 메뉴</RouterLink>
+          <RouterLink v-else-if="authReady && !auth.user" to="/login" class="adminButton">로그인</RouterLink>
         </div>
         </div>
       </aside>
@@ -567,9 +577,6 @@ function submitGlobalSearch() {
                 </button>
               </section>
             </template>
-            <button class="guideDockButton" type="button" aria-label="사용법 열기" @click="openGuideModal()">
-              <SvgIcon :src="iconMenuBook" :size="22" />
-            </button>
           </div>
         </div>
       </aside>
@@ -960,6 +967,7 @@ function submitGlobalSearch() {
   display: inline-flex;
   justify-content: center;
   align-items: center;
+  gap: 8px;
   padding: 12px 14px;
   border-radius: 14px;
   border: 1px solid rgba(255, 255, 255, 0.12);
@@ -970,6 +978,14 @@ function submitGlobalSearch() {
   font-weight: 800;
 }
 
+.adminButton--icon {
+  text-align: center;
+}
+
+.adminButton__icon {
+  flex: 0 0 auto;
+}
+
 .appMain {
   min-width: 0;
   min-height: 0;
@@ -1084,25 +1100,6 @@ function submitGlobalSearch() {
   padding-top: 12px;
 }
 
-.guideDockButton {
-  width: 42px;
-  height: 42px;
-  border-radius: 14px;
-  border: 1px solid rgba(255, 255, 255, 0.08);
-  background: rgba(255, 255, 255, 0.04);
-  color: rgba(255, 255, 255, 0.78);
-  display: inline-flex;
-  align-items: center;
-  justify-content: center;
-  cursor: pointer;
-  flex: 0 0 auto;
-}
-
-.guideDockButton:hover {
-  background: rgba(255, 255, 255, 0.08);
-  color: rgba(255, 255, 255, 0.96);
-}
-
 .rightRailAction__button {
   width: 100%;
   padding: 12px 14px;
diff --git a/frontend/src/stores/auth.js b/frontend/src/stores/auth.js
index 59c330c..27ebf26 100644
--- a/frontend/src/stores/auth.js
+++ b/frontend/src/stores/auth.js
@@ -5,30 +5,40 @@ export const useAuthStore = defineStore('auth', {
   state: () => ({
     user: null,
     status: 'idle',
+    hydrated: false,
   }),
   actions: {
     async refresh() {
+      if (this.status === 'loading') return this.user
       this.status = 'loading'
       try {
         const data = await api.me()
         this.user = data.user
+        return this.user
+      } catch (error) {
+        this.user = null
+        return null
       } finally {
         this.status = 'idle'
+        this.hydrated = true
       }
     },
     async signup(email, password) {
       const user = await api.signup({ email, password })
       this.user = user
+      this.hydrated = true
       return user
     },
     async login(email, password) {
       const user = await api.login({ email, password })
       this.user = user
+      this.hydrated = true
       return user
     },
     async logout() {
       await api.logout()
       this.user = null
+      this.hydrated = true
     },
   },
 })
diff --git a/frontend/src/views/LoginView.vue b/frontend/src/views/LoginView.vue
index 991da1a..cf9abd3 100644
--- a/frontend/src/views/LoginView.vue
+++ b/frontend/src/views/LoginView.vue
@@ -30,8 +30,15 @@ const description = computed(() =>
     : '저장한 티어표와 즐겨찾기, 프로필 설정을 이어서 관리할 수 있어요.'
 )
 const submitLabel = computed(() => (mode.value === 'signup' ? '가입하기' : '로그인'))
+const authReady = computed(() => auth.hydrated)
+const checkingSession = computed(() => !authReady.value || auth.status === 'loading')
 
 onMounted(async () => {
+  if (!auth.hydrated) await auth.refresh()
+  if (auth.user) {
+    router.replace(typeof route.query.redirect === 'string' ? route.query.redirect : '/me')
+    return
+  }
   try {
     const meta = await api.authMeta()
     hasUsers.value = !!meta.hasUsers
@@ -40,6 +47,15 @@ onMounted(async () => {
   }
 })
 
+watch(
+  () => [auth.hydrated, auth.user],
+  ([hydrated, user]) => {
+    if (!hydrated || !user) return
+    router.replace(typeof route.query.redirect === 'string' ? route.query.redirect : '/me')
+  },
+  { immediate: true }
+)
+
 async function submit() {
   error.value = ''
   if (mode.value === 'signup' && password.value !== passwordConfirm.value) {
@@ -66,7 +82,11 @@ async function submit() {
       </div>
     </header>
 
-    <section class="authScreen">
+    <section v-if="checkingSession" class="authScreen authScreen--loading">
+      <div class="authLoading">로그인 상태를 확인하고 있어요.</div>
+    </section>
+
+    <section v-else class="authScreen">
       <div class="authTabs" role="tablist" aria-label="로그인 또는 회원가입">
         <button type="button" class="authTabs__button" :class="{ 'authTabs__button--active': mode === 'login' }" @click="mode = 'login'">
           로그인
@@ -128,6 +148,16 @@ async function submit() {
   padding-top: 4px;
 }
 
+.authScreen--loading {
+  min-height: 220px;
+  align-items: center;
+}
+
+.authLoading {
+  color: rgba(255, 255, 255, 0.62);
+  font-size: 15px;
+}
+
 .authTabs {
   display: inline-flex;
   gap: 8px;
diff --git a/frontend/src/views/ProfileView.vue b/frontend/src/views/ProfileView.vue
index db0b43f..de1bf8b 100644
--- a/frontend/src/views/ProfileView.vue
+++ b/frontend/src/views/ProfileView.vue
@@ -30,14 +30,19 @@ const avatarUrl = computed(() => {
   return toApiUrl(auth.user.avatarSrc)
 })
 
+const authReady = computed(() => auth.hydrated)
+
 const displayInitial = computed(() => {
   const email = auth.user?.email || 'U'
   return email[0].toUpperCase()
 })
 
 onMounted(async () => {
-  await auth.refresh()
-  if (!auth.user) router.push('/login')
+  if (!auth.hydrated) await auth.refresh()
+  if (!auth.user) {
+    router.replace('/login')
+    return
+  }
   nickname.value = auth.user?.nickname || ''
   removeAvatar.value = false
 })
@@ -121,7 +126,11 @@ async function logout() {
       </div>
     </header>
 
-    <section v-if="auth.user" class="settingsScreen">
+    <section v-if="!authReady" class="settingsScreen settingsScreen--loading">
+      <div class="settingsLoading">계정 정보를 불러오고 있어요.</div>
+    </section>
+
+    <section v-else-if="auth.user" class="settingsScreen">
       <div class="settingsIdentity">
         <div class="avatarButtonWrap">
           <button class="avatarButton" type="button" @click="openAvatarPicker">
@@ -185,6 +194,16 @@ async function logout() {
   padding-top: 4px;
 }
 
+.settingsScreen--loading {
+  min-height: 240px;
+  align-items: center;
+}
+
+.settingsLoading {
+  color: rgba(255, 255, 255, 0.62);
+  font-size: 15px;
+}
+
 .settingsIdentity {
   display: grid;
   grid-template-columns: 120px minmax(0, 1fr);