diff --git a/src/app/(page)/disputes/[id]/DisputePage.module.scss b/src/app/(page)/disputes/[id]/DisputePage.module.scss
index 4d6b127..435659b 100644
--- a/src/app/(page)/disputes/[id]/DisputePage.module.scss
+++ b/src/app/(page)/disputes/[id]/DisputePage.module.scss
@@ -314,6 +314,21 @@
 // Modal
 // ===========================
 
+.modalContent {
+  display: flex;
+  flex-direction: column;
+  gap: fn.r(20);
+}
+
+.modalMessage {
+  font-family: v.$font-family-base;
+  font-size: v.$font-size-title-s;
+  font-weight: v.$font-weight-semibold;
+  line-height: v.$line-height-title-s;
+  color: var(--text-primary);
+  white-space: pre-line;
+}
+
 .modalOverlay {
   position: fixed;
   inset: 0;
diff --git a/src/app/(page)/disputes/[id]/page.tsx b/src/app/(page)/disputes/[id]/page.tsx
index f5e7f88..572564c 100644
--- a/src/app/(page)/disputes/[id]/page.tsx
+++ b/src/app/(page)/disputes/[id]/page.tsx
@@ -14,6 +14,7 @@ import Spinner from '@/components/ui/Spinner';
 import StatusBadge from '@/components/ui/StatusBadge';
 import CategoryIcon from '@/components/ui/CategoryIcon';
 import InviteChoiceModal from '@/components/room/InviteChoiceModal';
+import Modal from '@/components/ui/Modal';
 import JudgmentResult from '@/components/judgement/JudgmentResult';
 import JudgmentTypeResult from '@/components/judgement/JudgmentTypeResult';
 import {
@@ -100,6 +101,7 @@ export default function DisputePage({ params }: { params: Promise<{ id: string }
     data: judgment,
     isLoading: judgmentLoading,
     isError: judgmentError,
+    error: judgmentErrorData,
   } = useJudgment(id, isCompleted);
 
   const showToast = useToastStore((s) => s.show);
@@ -108,8 +110,19 @@ export default function DisputePage({ params }: { params: Promise<{ id: string }
   const [judgmentSubTab, setJudgmentSubTab] = React.useState<'verdict' | 'type'>('verdict');
   const [showSoloModal, setShowSoloModal] = React.useState(false);
   const [isInviting, setIsInviting] = React.useState(false);
+  const [judgmentErrorModal, setJudgmentErrorModal] = React.useState(false);
+  const [judgmentErrorMessage, setJudgmentErrorMessage] = React.useState<string | null>(null);
   const [isRefreshing, setIsRefreshing] = React.useState(false);
 
+  React.useEffect(() => {
+    if (judgmentError && !judgmentErrorModal) {
+      setJudgmentErrorMessage(
+        judgmentErrorData instanceof Error ? judgmentErrorData.message : '판결 결과를 불러올 수 없습니다.',
+      );
+      setJudgmentErrorModal(true);
+    }
+  }, [judgmentError]);
+
   const handleRefresh = async () => {
     setIsRefreshing(true);
     try {
@@ -148,7 +161,7 @@ export default function DisputePage({ params }: { params: Promise<{ id: string }
   const runJudge = () => {
     setShowSoloModal(false);
     requestJudgment(undefined, {
-      onSuccess: () => window.location.reload(),
+      onSuccess: () => queryClient.invalidateQueries({ queryKey: disputeKeys.detail(id) }),
       onError: (error) =>
         showToast(error instanceof Error ? error.message : 'AI 판결 요청에 실패했습니다.'),
     });
@@ -347,6 +360,15 @@ export default function DisputePage({ params }: { params: Promise<{ id: string }
         onAlone={() => void runJudge()}
         onInvite={() => void handleInvite()}
       />
+
+      <Modal open={judgmentErrorModal}>
+        <div className={styles.modalContent}>
+          <p className={styles.modalMessage}>
+            {judgmentErrorMessage ?? '판결 결과를 불러올 수 없습니다.'}
+          </p>
+          <Button onClick={() => setJudgmentErrorModal(false)}>확인</Button>
+        </div>
+      </Modal>
     </div>
   );
 }
diff --git a/src/app/(page)/mypage/edit/page.tsx b/src/app/(page)/mypage/edit/page.tsx
index 9b45175..ae65006 100644
--- a/src/app/(page)/mypage/edit/page.tsx
+++ b/src/app/(page)/mypage/edit/page.tsx
@@ -22,6 +22,7 @@ export default function ProfileEditPage() {
     return () => setHeader(null)
   }, [])
   const fileInputRef = useRef<HTMLInputElement>(null);
+  const blobUrlRef = useRef<string | null>(null);
 
   const { data: user, isLoading, isError, error } = useUserMe();
   const updateProfile = useUpdateProfile();
@@ -43,23 +44,23 @@ export default function ProfileEditPage() {
     }
   }, [user, reset]);
 
+  useEffect(() => {
+    return () => {
+      if (blobUrlRef.current) URL.revokeObjectURL(blobUrlRef.current);
+    };
+  }, []);
+
   const handleImageChange = (e: React.ChangeEvent<HTMLInputElement>) => {
     const file = e.target.files?.[0];
     if (!file) return;
 
-    if (previewUrl?.startsWith('blob:')) {
-      URL.revokeObjectURL(previewUrl);
-    }
+    const prevUrl = blobUrlRef.current;
     const objectUrl = URL.createObjectURL(file);
+    blobUrlRef.current = objectUrl;
     setPreviewUrl(objectUrl);
+    if (prevUrl) setTimeout(() => URL.revokeObjectURL(prevUrl), 0);
   };
 
-  useEffect(() => {
-    return () => {
-      if (previewUrl?.startsWith('blob:')) URL.revokeObjectURL(previewUrl);
-    };
-  }, [previewUrl]);
-
   const validate = () => {
     const next: Record<string, string> = {};
 
diff --git a/src/app/(page)/privacy/page.tsx b/src/app/(page)/privacy/page.tsx
index 72f59c2..248b490 100644
--- a/src/app/(page)/privacy/page.tsx
+++ b/src/app/(page)/privacy/page.tsx
@@ -1,23 +1,11 @@
-'use client';
-
-import { useRouter } from 'next/navigation';
-import ArrowBackIosNewIcon from '@mui/icons-material/ArrowBackIosNew';
+import BackButton from '@/components/ui/BackButton';
 import styles from './privacy.module.scss';
 
 export default function PrivacyPage() {
-  const router = useRouter();
-
   return (
     <div className={styles.page}>
       <header className={styles.header}>
-        <button
-          type="button"
-          className={styles.backButton}
-          onClick={() => router.back()}
-          aria-label="뒤로 가기"
-        >
-          <ArrowBackIosNewIcon />
-        </button>
+        <BackButton className={styles.backButton} />
         <h1 className={styles.title}>개인정보 처리방침</h1>
         <span className={styles.spacer} />
       </header>
diff --git a/src/app/(page)/terms/page.tsx b/src/app/(page)/terms/page.tsx
index cb5b6ad..3bfa8d4 100644
--- a/src/app/(page)/terms/page.tsx
+++ b/src/app/(page)/terms/page.tsx
@@ -1,23 +1,11 @@
-'use client';
-
-import { useRouter } from 'next/navigation';
-import ArrowBackIosNewIcon from '@mui/icons-material/ArrowBackIosNew';
+import BackButton from '@/components/ui/BackButton';
 import styles from './terms.module.scss';
 
 export default function TermsPage() {
-  const router = useRouter();
-
   return (
     <div className={styles.page}>
       <header className={styles.header}>
-        <button
-          type="button"
-          className={styles.backButton}
-          onClick={() => router.back()}
-          aria-label="뒤로 가기"
-        >
-          <ArrowBackIosNewIcon />
-        </button>
+        <BackButton className={styles.backButton} />
         <h1 className={styles.title}>이용약관</h1>
         <span className={styles.spacer} />
       </header>
diff --git a/src/app/api/calendar/route.ts b/src/app/api/calendar/route.ts
index d3136ee..affcbe3 100644
--- a/src/app/api/calendar/route.ts
+++ b/src/app/api/calendar/route.ts
@@ -1,8 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server';
-import { getServerSession } from 'next-auth';
-import { authOptions } from '@/lib/auth';
 import { prisma } from '@/lib/db';
-import { getSessionUserId } from '@/lib/auth/session';
+import { getRequestUserId } from '@/lib/auth/session';
 import type { ApiResponse } from '@/types/common';
 import type { CalendarMonthResponse, CalendarRecordItem } from '@/types/calendar';
 
@@ -10,8 +8,7 @@ import type { CalendarMonthResponse, CalendarRecordItem } from '@/types/calendar
 // 해당 월의 날짜별 감정일기/사건 요약 반환 (달력 마킹용)
 export async function GET(request: NextRequest) {
   try {
-    const session = await getServerSession(authOptions);
-    const userId = getSessionUserId(session);
+    const userId = await getRequestUserId(request);
     if (!userId) {
       return NextResponse.json<ApiResponse>(
         { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/diary/route.ts b/src/app/api/diary/route.ts
index 1c8c208..27ad5c9 100644
--- a/src/app/api/diary/route.ts
+++ b/src/app/api/diary/route.ts
@@ -1,16 +1,13 @@
 import { NextRequest, NextResponse } from 'next/server';
-import { getServerSession } from 'next-auth';
-import { authOptions } from '@/lib/auth';
 import { prisma } from '@/lib/db';
-import { getSessionUserId } from '@/lib/auth/session';
+import { getRequestUserId } from '@/lib/auth/session';
 import type { ApiResponse } from '@/types/common';
 import type { DiaryItem } from '@/types/diary';
 
 // GET /api/diary?date=2026-06-16
 // 특정 날짜의 감정일기 목록 조회. 최신순 정렬. 본인 데이터만 반환
 export async function GET(request: NextRequest) {
-  const session = await getServerSession(authOptions);
-  const userId = getSessionUserId(session);
+  const userId = await getRequestUserId(request);
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/disputes/[id]/judge/route.ts b/src/app/api/disputes/[id]/judge/route.ts
index 38f9ccf..427abdf 100644
--- a/src/app/api/disputes/[id]/judge/route.ts
+++ b/src/app/api/disputes/[id]/judge/route.ts
@@ -1,9 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
 import type { DisputeStatus } from '@prisma/client'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import { generateAiJudgment } from '@/lib/ai/judgment'
 import { toAiJudgmentDto } from '@/domains/judgement/judgment.mapper'
 import type { ApiResponse } from '@/types/common'
@@ -15,8 +13,7 @@ export async function POST(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/disputes/[id]/result/route.ts b/src/app/api/disputes/[id]/result/route.ts
index 11e1f04..2f4a9af 100644
--- a/src/app/api/disputes/[id]/result/route.ts
+++ b/src/app/api/disputes/[id]/result/route.ts
@@ -1,8 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import { toAiJudgmentDto } from '@/domains/judgement/judgment.mapper'
 import type { ApiResponse } from '@/types/common'
 import type { AiJudgmentDto } from '@/types/judgment'
@@ -13,8 +11,7 @@ export async function GET(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
@@ -25,11 +22,25 @@ export async function GET(
   const { id } = await params
 
   try {
-    // 존재 확인 먼저, 권한 확인은 그 이후 (정보 노출 방지)
+    // dispute 조회 + 참여자 권한 확인 + judgment를 단일 쿼리로 처리
     const dispute = await prisma.dispute.findFirst({
-      where: { id, deletedAt: null },
-      select: { status: true },
+      where: {
+        id,
+        deletedAt: null,
+        participants: { some: { userId } },
+      },
+      select: {
+        status: true,
+        aiJudgment: {
+          include: {
+            resultConflictDetail: true,
+            resultCard: true,
+            aiNotice: true,
+          },
+        },
+      },
     })
+
     if (!dispute) {
       return NextResponse.json<ApiResponse>(
         { success: false, error: { code: 'DISPUTE_NOT_FOUND', message: '사건을 찾을 수 없습니다.' } },
@@ -37,16 +48,6 @@ export async function GET(
       )
     }
 
-    const participant = await prisma.disputeParticipant.findFirst({
-      where: { disputeId: id, userId },
-    })
-    if (!participant) {
-      return NextResponse.json<ApiResponse>(
-        { success: false, error: { code: 'FORBIDDEN', message: '판결 결과를 조회할 권한이 없습니다.' } },
-        { status: 403 },
-      )
-    }
-
     if (dispute.status === 'JUDGING') {
       return NextResponse.json<ApiResponse>(
         {
@@ -74,14 +75,7 @@ export async function GET(
       )
     }
 
-    const judgment = await prisma.aiJudgment.findFirst({
-      where: { disputeId: id },
-      include: {
-        resultConflictDetail: true,
-        resultCard: true,
-        aiNotice: true,
-      },
-    })
+    const judgment = dispute.aiJudgment
     if (!judgment) {
       return NextResponse.json<ApiResponse>(
         {
diff --git a/src/app/api/disputes/[id]/route.ts b/src/app/api/disputes/[id]/route.ts
index 71ec1d9..d614847 100644
--- a/src/app/api/disputes/[id]/route.ts
+++ b/src/app/api/disputes/[id]/route.ts
@@ -1,10 +1,8 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
 import { z } from 'zod'
 import { type Prisma, type CategoryGroup as PrismaCategoryGroup } from '@prisma/client'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import { VALID_CATEGORY_GROUPS, IMMUTABLE_DISPUTE_STATUSES } from '@/lib/constants/dispute'
 import type { ApiResponse, CategoryGroup } from '@/types/common'
 import type { DisputeDto, DisputeParticipantDto, DisputeStatementDto } from '@/types/dispute'
@@ -85,8 +83,7 @@ export async function GET(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
@@ -135,8 +132,7 @@ export async function PATCH(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
@@ -245,8 +241,7 @@ export async function DELETE(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/disputes/[id]/statements/route.ts b/src/app/api/disputes/[id]/statements/route.ts
index 6130e91..47e4d9b 100644
--- a/src/app/api/disputes/[id]/statements/route.ts
+++ b/src/app/api/disputes/[id]/statements/route.ts
@@ -1,10 +1,8 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
 import { z } from 'zod'
 import { Prisma, type DisputeStatus, type DisputeStatement } from '@prisma/client'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import { moderateContent } from '@/lib/ai/moderation'
 import { extractDisputeMeta } from '@/lib/ai/judgment'
 import type { ApiResponse } from '@/types/common'
@@ -39,8 +37,7 @@ export async function POST(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  let userId = getSessionUserId(session)
+  let userId = await getRequestUserId(request)
 
   if (!userId) {
     if (!DEV_BYPASS) {
diff --git a/src/app/api/disputes/[id]/statements/submit/route.ts b/src/app/api/disputes/[id]/statements/submit/route.ts
index 9c0f589..cde2b28 100644
--- a/src/app/api/disputes/[id]/statements/submit/route.ts
+++ b/src/app/api/disputes/[id]/statements/submit/route.ts
@@ -1,19 +1,16 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import type { ApiResponse } from '@/types/common'
 import type { DisputeStatus, StatementSubmitResponse } from '@/types/dispute'
 
 // POST /api/disputes/:id/statements/submit
 // 진술 최종 제출. submittedAt 설정 후 dispute 상태 업데이트. 멱등성 보장.
 export async function POST(
-  _request: NextRequest,
+  request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
 
   if (!userId) {
     return NextResponse.json<ApiResponse>(
diff --git a/src/app/api/disputes/[id]/status/route.ts b/src/app/api/disputes/[id]/status/route.ts
index 1c3da4b..1e7e440 100644
--- a/src/app/api/disputes/[id]/status/route.ts
+++ b/src/app/api/disputes/[id]/status/route.ts
@@ -1,9 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
 import { z } from 'zod'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import type { ApiResponse } from '@/types/common'
 import type { DisputeStatus } from '@/types/dispute'
 
@@ -21,8 +19,7 @@ export async function PATCH(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/disputes/route.ts b/src/app/api/disputes/route.ts
index 126c4c6..051107c 100644
--- a/src/app/api/disputes/route.ts
+++ b/src/app/api/disputes/route.ts
@@ -1,10 +1,8 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
 import { z } from 'zod'
 import { type Prisma, type CategoryGroup as PrismaCategoryGroup, DisputeStatus } from '@prisma/client'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import { VALID_CATEGORY_GROUPS } from '@/lib/constants/dispute'
 import type { ApiResponse, CategoryGroup } from '@/types/common'
 import type { DisputeDto, DisputeParticipantDto, DisputeListResponse } from '@/types/dispute'
@@ -57,8 +55,7 @@ function toDisputeDto(dispute: DisputeForList): DisputeDto {
 // GET /api/disputes
 // 내가 참여한 사건 목록 조회. categoryGroup으로 필터링, page/limit으로 페이지네이션
 export async function GET(request: NextRequest) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
@@ -148,8 +145,7 @@ export async function GET(request: NextRequest) {
 // POST /api/disputes
 // 사건 생성. 활성 방(ai_chat, invite_ready, one_to_one)에서 생성 가능. 생성자는 role_a로 확정
 export async function POST(request: NextRequest) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/rooms/[id]/close/route.ts b/src/app/api/rooms/[id]/close/route.ts
index 068b1b1..1d61cfb 100644
--- a/src/app/api/rooms/[id]/close/route.ts
+++ b/src/app/api/rooms/[id]/close/route.ts
@@ -1,8 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import type { ApiResponse } from '@/types/common'
 
 const CLOSEABLE_MODES = ['AI_ROOM', 'INVITE_READY', 'ONE_TO_ONE'] as const
@@ -13,8 +11,7 @@ export async function POST(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/rooms/[id]/invite/route.ts b/src/app/api/rooms/[id]/invite/route.ts
index 10eb767..414d7c4 100644
--- a/src/app/api/rooms/[id]/invite/route.ts
+++ b/src/app/api/rooms/[id]/invite/route.ts
@@ -1,8 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import { generateInviteToken, hashInviteToken, getInviteExpiresAt } from '@/lib/invite'
 import type { ApiResponse } from '@/types/common'
 
@@ -17,8 +15,7 @@ export async function POST(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/rooms/[id]/route.ts b/src/app/api/rooms/[id]/route.ts
index 0e9f533..a6b8e76 100644
--- a/src/app/api/rooms/[id]/route.ts
+++ b/src/app/api/rooms/[id]/route.ts
@@ -1,9 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
 import { type RoomMode as PrismaRoomMode, type CategoryGroup as PrismaCategoryGroup } from '@prisma/client'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import type { ApiResponse, CategoryGroup } from '@/types/common'
 import type { RoomDto, RoomMode } from '@/types/room'
 
@@ -49,8 +47,7 @@ export async function GET(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
@@ -94,8 +91,7 @@ export async function DELETE(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/rooms/join/[token]/route.ts b/src/app/api/rooms/join/[token]/route.ts
index 24a89f8..a4156b1 100644
--- a/src/app/api/rooms/join/[token]/route.ts
+++ b/src/app/api/rooms/join/[token]/route.ts
@@ -1,9 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
 import { type CategoryGroup as PrismaCategoryGroup } from '@prisma/client'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import { hashInviteToken } from '@/lib/invite'
 import type { ApiResponse } from '@/types/common'
 
@@ -27,8 +25,7 @@ export async function GET(
   request: NextRequest,
   { params }: { params: Promise<{ token: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
@@ -105,8 +102,7 @@ export async function POST(
   request: NextRequest,
   { params }: { params: Promise<{ token: string }> },
 ) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/rooms/route.ts b/src/app/api/rooms/route.ts
index ca8b9a4..75aef10 100644
--- a/src/app/api/rooms/route.ts
+++ b/src/app/api/rooms/route.ts
@@ -1,10 +1,8 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
 import { z } from 'zod'
 import { type RoomMode as PrismaRoomMode, type CategoryGroup as PrismaCategoryGroup } from '@prisma/client'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import { VALID_CATEGORY_GROUPS } from '@/lib/constants/dispute'
 import type { ApiResponse, CategoryGroup } from '@/types/common'
 import type { RoomDto, RoomListResponse, RoomMode } from '@/types/room'
@@ -50,8 +48,7 @@ function toRoomDto(room: {
 // GET /api/rooms
 // 내가 생성하거나 참여한 방 목록 조회
 export async function GET(request: NextRequest) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
@@ -98,8 +95,7 @@ export async function GET(request: NextRequest) {
 // POST /api/rooms
 // 방 생성. 기본 roomMode = ai_room
 export async function POST(request: NextRequest) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
   if (!userId) {
     return NextResponse.json<ApiResponse>(
       { success: false, error: { code: 'UNAUTHORIZED', message: '로그인이 필요합니다.' } },
diff --git a/src/app/api/user/me/profile-image/route.ts b/src/app/api/user/me/profile-image/route.ts
index b3d88d7..17904b0 100644
--- a/src/app/api/user/me/profile-image/route.ts
+++ b/src/app/api/user/me/profile-image/route.ts
@@ -1,8 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import { supabaseAdmin, PROFILE_IMAGES_BUCKET } from '@/lib/storage'
 import type { ApiResponse } from '@/types/common'
 
@@ -12,8 +10,7 @@ const MAX_FILE_SIZE = 5 * 1024 * 1024 // 5MB
 const ALLOWED_TYPES = ['image/jpeg', 'image/png', 'image/webp']
 
 export async function POST(request: NextRequest) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
 
   if (!userId) {
     return NextResponse.json<ApiResponse>(
diff --git a/src/app/api/user/me/route.ts b/src/app/api/user/me/route.ts
index 007a93c..2a3ef51 100644
--- a/src/app/api/user/me/route.ts
+++ b/src/app/api/user/me/route.ts
@@ -1,8 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server'
-import { getServerSession } from 'next-auth'
-import { authOptions } from '@/lib/auth'
 import { prisma } from '@/lib/db'
-import { getSessionUserId } from '@/lib/auth/session'
+import { getRequestUserId } from '@/lib/auth/session'
 import { supabaseAdmin, PROFILE_IMAGES_BUCKET } from '@/lib/storage'
 import type { ApiResponse } from '@/types/common'
 
@@ -64,9 +62,8 @@ function getAuthErrorResponse() {
   )
 }
 
-export async function GET() {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+export async function GET(request: NextRequest) {
+  const userId = await getRequestUserId(request)
 
   if (!userId) return getAuthErrorResponse()
 
@@ -105,8 +102,7 @@ export async function GET() {
 }
 
 export async function PATCH(request: NextRequest) {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+  const userId = await getRequestUserId(request)
 
   if (!userId) return getAuthErrorResponse()
 
@@ -271,9 +267,8 @@ export async function PATCH(request: NextRequest) {
   }
 }
 
-export async function DELETE() {
-  const session = await getServerSession(authOptions)
-  const userId = getSessionUserId(session)
+export async function DELETE(request: NextRequest) {
+  const userId = await getRequestUserId(request)
 
   if (!userId) return getAuthErrorResponse()
 
diff --git a/src/components/providers/QueryProvider.tsx b/src/components/providers/QueryProvider.tsx
index 0a2b6fa..a7db2b6 100644
--- a/src/components/providers/QueryProvider.tsx
+++ b/src/components/providers/QueryProvider.tsx
@@ -7,6 +7,8 @@ import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
 import { useState } from 'react';
 
 export default function QueryProvider({ children }: { children: React.ReactNode }) {
-  const [queryClient] = useState(() => new QueryClient());
+  const [queryClient] = useState(
+    () => new QueryClient({ defaultOptions: { queries: { retry: 0 } } }),
+  );
   return <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>;
 }
diff --git a/src/components/ui/BackButton.tsx b/src/components/ui/BackButton.tsx
new file mode 100644
index 0000000..ec1e119
--- /dev/null
+++ b/src/components/ui/BackButton.tsx
@@ -0,0 +1,22 @@
+'use client'
+
+import { useRouter } from 'next/navigation'
+import ArrowBackIosNewIcon from '@mui/icons-material/ArrowBackIosNew'
+
+interface BackButtonProps {
+  className?: string
+}
+
+export default function BackButton({ className }: BackButtonProps) {
+  const router = useRouter()
+  return (
+    <button
+      type="button"
+      className={className}
+      onClick={() => router.back()}
+      aria-label="뒤로 가기"
+    >
+      <ArrowBackIosNewIcon />
+    </button>
+  )
+}
diff --git a/src/components/ui/Modal.module.scss b/src/components/ui/Modal.module.scss
index c0d8ede..313b684 100644
--- a/src/components/ui/Modal.module.scss
+++ b/src/components/ui/Modal.module.scss
@@ -9,9 +9,8 @@
 .paper {
   width: calc(100% - fn.r(40));
   max-width: fn.r(360);
-  border-radius: fn.r(8) !important;
   border: 2px solid v.$color-black-700 !important;
-  border-radius: fn.r(16) !important;
+  border-radius: fn.r(8) !important;
   padding: fn.r(24) fn.r(20) fn.r(20);
   box-shadow: 0 fn.r(4) fn.r(24) rgba(0, 0, 0, 0.12);
 }
diff --git a/src/domains/dispute/dispute.hooks.ts b/src/domains/dispute/dispute.hooks.ts
index 5b2f86a..c46de30 100644
--- a/src/domains/dispute/dispute.hooks.ts
+++ b/src/domains/dispute/dispute.hooks.ts
@@ -45,6 +45,7 @@ export function useDispute(
     queryKey: disputeKeys.detail(disputeId),
     queryFn: () => fetchDispute(disputeId),
     enabled: !!disputeId,
+    staleTime: 1000 * 30,
     refetchInterval: options?.refetchInterval,
   });
 }
diff --git a/src/domains/judgement/judgement.hooks.ts b/src/domains/judgement/judgement.hooks.ts
index 0b2ae20..48b80ff 100644
--- a/src/domains/judgement/judgement.hooks.ts
+++ b/src/domains/judgement/judgement.hooks.ts
@@ -13,5 +13,6 @@ export function useJudgment(disputeId: string, enabled = true) {
     queryKey: judgementKeys.detail(disputeId),
     queryFn: () => fetchJudgment(disputeId),
     enabled: !!disputeId && enabled,
+    staleTime: 1000 * 60 * 10,
   })
 }
diff --git a/src/lib/auth/session.ts b/src/lib/auth/session.ts
index 7b53426..6f1aa7c 100644
--- a/src/lib/auth/session.ts
+++ b/src/lib/auth/session.ts
@@ -1,7 +1,15 @@
+import type { NextRequest } from 'next/server'
 import type { Session } from 'next-auth'
+import { getToken } from 'next-auth/jwt'
 
 // NextAuth v4는 기본 Session 타입에 user.id를 포함하지 않음
 // authOptions의 callbacks.session에서 token.sub를 user.id로 추가해야 함
 export function getSessionUserId(session: Session | null | undefined): string | undefined {
   return (session?.user as { id?: string } | undefined)?.id
 }
+
+// getServerSession 대신 getToken을 사용해 JWT 파싱만 수행 (callback 실행 없음)
+export async function getRequestUserId(req: NextRequest): Promise<string | undefined> {
+  const token = await getToken({ req, secret: process.env.NEXTAUTH_SECRET })
+  return token?.sub ?? undefined
+}