fix(exit-hold): bar 진행 표시 즉시 반영 및 리셋 애니메이션 수정

맥락:

- 몰입 OFF의 나가기 롱프레스 bar에서 진행 표시가 즉시 보이지 않고 완료 시 0으로 역방향 축소되는 문제를 해결하기 위해

변경사항:

- bar 진행 표시를 JS width 갱신에서 CSS keyframes 기반으로 교체

- 키프레임에 가속 규칙 반영(0.05초 20%, 1.0초 100%)

- 완료 후 100% 상태를 짧게 유지한 뒤 언마운트하도록 훅 상태(isCompleted) 보강

- progress fill의 rounded 캡을 제거해 끝단 직선화

- docs/90_current_state.md, docs/session_brief.md 최신 상태 반영

검증:

- npx tsc --noEmit

세션-상태: bar 롱프레스 진행은 눌렀을 때 즉시 보이고 완료 리셋 시 역방향 축소가 사라짐

세션-다음: 롱프레스 인지성 보조 카피 도입 여부 검토

세션-리스크: bar(CSS)와 ring(JS) 진행 로직이 분리되어 향후 규칙 변경 시 동시 점검 필요

src/app/globals.css

@@ -37,3 +37,15 @@ body {
     transform: translateX(0);
   }
 }
+
+@keyframes exit-hold-bar-fill {
+  0% {
+    transform: scaleX(0);
+  }
+  5% {
+    transform: scaleX(0.2);
+  }
+  100% {
+    transform: scaleX(1);
+  }
+}

src/features/exit-hold/model/useHoldToConfirm.ts

@@ -1,9 +1,10 @@
 'use client';
 
-import { useRef, useState } from 'react';
+import { useEffect, useRef, useState } from 'react';
 
 const HOLD_DURATION_MS = 1000;
 const BOOST_DURATION_MS = 50;
+const COMPLETE_HOLD_MS = 160;
 
 const mapProgress = (elapsedMs: number) => {
   if (elapsedMs <= 0) {
@@ -20,10 +21,13 @@ const mapProgress = (elapsedMs: number) => {
 
 export const useHoldToConfirm = (onConfirm: () => void) => {
   const frameRef = useRef<number | null>(null);
+  const confirmTimeoutRef = useRef<number | null>(null);
+  const completeTimeoutRef = useRef<number | null>(null);
   const startRef = useRef<number | null>(null);
   const confirmedRef = useRef(false);
   const [progress, setProgress] = useState(0);
   const [isHolding, setHolding] = useState(false);
+  const [isCompleted, setCompleted] = useState(false);
 
   const clearFrame = () => {
     if (frameRef.current !== null) {
@@ -32,14 +36,35 @@ export const useHoldToConfirm = (onConfirm: () => void) => {
     }
   };
 
-  const reset = () => {
+  const clearTimers = () => {
+    if (confirmTimeoutRef.current !== null) {
+      window.clearTimeout(confirmTimeoutRef.current);
+      confirmTimeoutRef.current = null;
+    }
+
+    if (completeTimeoutRef.current !== null) {
+      window.clearTimeout(completeTimeoutRef.current);
+      completeTimeoutRef.current = null;
+    }
+  };
+
+  const reset = (withCompleted = false) => {
     clearFrame();
+    clearTimers();
     startRef.current = null;
     confirmedRef.current = false;
     setHolding(false);
+    setCompleted(withCompleted);
     setProgress(0);
   };
 
+  useEffect(() => {
+    return () => {
+      clearFrame();
+      clearTimers();
+    };
+  }, []);
+
   const step = () => {
     if (startRef.current === null) {
       return;
@@ -52,10 +77,17 @@ export const useHoldToConfirm = (onConfirm: () => void) => {
 
     if (clampedProgress >= 1 && !confirmedRef.current) {
       confirmedRef.current = true;
+      if (confirmTimeoutRef.current !== null) {
+        window.clearTimeout(confirmTimeoutRef.current);
+        confirmTimeoutRef.current = null;
+      }
+      setHolding(false);
+      setCompleted(true);
       onConfirm();
-      window.setTimeout(() => {
-        reset();
-      }, 120);
+
+      completeTimeoutRef.current = window.setTimeout(() => {
+        reset(false);
+      }, COMPLETE_HOLD_MS);
       return;
     }
 
@@ -63,15 +95,32 @@ export const useHoldToConfirm = (onConfirm: () => void) => {
   };
 
   const start = () => {
-    if (isHolding) {
+    if (isHolding || isCompleted) {
       return;
     }
 
+    clearTimers();
     clearFrame();
     confirmedRef.current = false;
-    startRef.current = performance.now();
+    setCompleted(false);
+    setProgress(0);
     setHolding(true);
+    startRef.current = performance.now();
     frameRef.current = window.requestAnimationFrame(step);
+    confirmTimeoutRef.current = window.setTimeout(() => {
+      if (!confirmedRef.current) {
+        confirmedRef.current = true;
+        confirmTimeoutRef.current = null;
+        setProgress(1);
+        setHolding(false);
+        setCompleted(true);
+        onConfirm();
+
+        completeTimeoutRef.current = window.setTimeout(() => {
+          reset(false);
+        }, COMPLETE_HOLD_MS);
+      }
+    }, HOLD_DURATION_MS);
   };
 
   const cancel = () => {
@@ -85,6 +134,7 @@ export const useHoldToConfirm = (onConfirm: () => void) => {
   return {
     progress,
     isHolding,
+    isCompleted,
     start,
     cancel,
   };

src/features/exit-hold/ui/ExitHoldButton.tsx

@@ -18,7 +18,7 @@ export const ExitHoldButton = ({
   onConfirm,
   className,
 }: ExitHoldButtonProps) => {
-  const { progress, isHolding, start, cancel } = useHoldToConfirm(onConfirm);
+  const { progress, isHolding, isCompleted, start, cancel } = useHoldToConfirm(onConfirm);
   const ringOffset = RING_CIRCUMFERENCE * (1 - progress);
 
   const handleKeyDown = (event: KeyboardEvent<HTMLButtonElement>) => {
@@ -101,15 +101,20 @@ export const ExitHoldButton = ({
       onKeyUp={handleKeyUp}
       onClick={(event) => event.preventDefault()}
       className={cn(
-        'group relative overflow-hidden rounded-lg bg-white/8 px-2.5 py-1.5 text-xs text-white/82 transition hover:bg-white/14 hover:text-white focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-sky-200/80',
+        'relative overflow-hidden rounded-lg bg-white/8 px-2.5 py-1.5 text-xs text-white/82 transition hover:bg-white/14 hover:text-white focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-sky-200/80',
         className,
       )}
     >
-      <span
-        aria-hidden
-        className="absolute inset-y-0 left-0 rounded-lg bg-sky-200/24 transition-[width] duration-75"
-        style={{ width: `${progress * 100}%` }}
-      />
+      {isHolding || isCompleted ? (
+        <span
+          aria-hidden
+          className={cn(
+            'absolute inset-0 z-0 origin-left transform-gpu bg-sky-200/24 rounded-none',
+            isHolding && 'animate-[exit-hold-bar-fill_1000ms_linear_forwards]',
+          )}
+          style={isCompleted ? { transform: 'scaleX(1)' } : undefined}
+        />
+      ) : null}
       <span className="relative z-10 inline-flex items-center gap-1">
         <span aria-hidden>⤫</span>
         <span>나가기</span>