chore(state): /space 선택 상태와 override 로컬 저장/복원 추가

맥락:
- 새로고침 시 Scene/Timer/Sound와 override가 초기화되면 추천 자동화 체감이 끊겨 사용성이 떨어졌습니다.

변경사항:
- /space workspace에 localStorage 기반 상태 저장/복원 키(viberoom:workspace-selection:v1)를 추가했습니다.
- sceneId, timerPresetId, soundPresetId, override.sound/timer를 저장하고 진입 시 복원하도록 반영했습니다.
- 복원 우선순위는 쿼리 파라미터 > 저장 상태 > Scene 추천값 순으로 정리했습니다.

검증:
- npx tsc --noEmit

세션-상태: 새로고침 후에도 마지막 Scene/Timer/Sound 및 override 상태가 유지됩니다.
세션-다음: 세션 문서(90_current_state/session_brief) 업데이트와 최종 정리를 진행합니다.
세션-리스크: 저장 포맷 변경 시 이전 localStorage 데이터와의 호환성 점검이 필요합니다.

src/widgets/space-workspace/ui/SpaceWorkspaceWidget.tsx

@@ -26,20 +26,64 @@ type SelectionOverride = {
   sound: boolean;
   timer: boolean;
 };
+interface StoredWorkspaceSelection {
+  sceneId?: string;
+  timerPresetId?: string;
+  soundPresetId?: string;
+  override?: Partial<SelectionOverride>;
+}
 
-const resolveInitialRoomId = (roomIdFromQuery: string | null) => {
+const WORKSPACE_SELECTION_STORAGE_KEY = 'viberoom:workspace-selection:v1';
+
+const readStoredWorkspaceSelection = (): StoredWorkspaceSelection => {
+  if (typeof window === 'undefined') {
+    return {};
+  }
+
+  const raw = window.localStorage.getItem(WORKSPACE_SELECTION_STORAGE_KEY);
+
+  if (!raw) {
+    return {};
+  }
+
+  try {
+    const parsed = JSON.parse(raw);
+
+    if (!parsed || typeof parsed !== 'object') {
+      return {};
+    }
+
+    return parsed as StoredWorkspaceSelection;
+  } catch {
+    return {};
+  }
+};
+
+const resolveInitialRoomId = (roomIdFromQuery: string | null, storedSceneId?: string) => {
   if (roomIdFromQuery && getRoomById(roomIdFromQuery)) {
     return roomIdFromQuery;
   }
 
+  if (storedSceneId && getRoomById(storedSceneId)) {
+    return storedSceneId;
+  }
+
   return ROOM_THEMES[0].id;
 };
 
-const resolveInitialSoundPreset = (presetIdFromQuery: string | null, recommendedPresetId?: string) => {
+const resolveInitialSoundPreset = (
+  presetIdFromQuery: string | null,
+  storedPresetId: string | undefined,
+  recommendedPresetId?: string,
+) => {
   if (presetIdFromQuery && SOUND_PRESETS.some((preset) => preset.id === presetIdFromQuery)) {
     return presetIdFromQuery;
   }
 
+  if (storedPresetId && SOUND_PRESETS.some((preset) => preset.id === storedPresetId)) {
+    return storedPresetId;
+  }
+
   if (recommendedPresetId && SOUND_PRESETS.some((preset) => preset.id === recommendedPresetId)) {
     return recommendedPresetId;
   }
@@ -66,11 +110,26 @@ const resolveTimerLabelFromPresetId = (presetId?: string) => {
   return preset.label;
 };
 
-const resolveInitialTimerLabel = (timerLabelFromQuery: string | null, recommendedPresetId?: string) => {
+const resolveTimerPresetIdFromLabel = (timerLabel: string) => {
+  const preset = TIMER_SELECTION_PRESETS.find((candidate) => candidate.label === timerLabel);
+  return preset?.id;
+};
+
+const resolveInitialTimerLabel = (
+  timerLabelFromQuery: string | null,
+  storedPresetId?: string,
+  recommendedPresetId?: string,
+) => {
   if (timerLabelFromQuery && TIMER_SELECTION_PRESETS.some((preset) => preset.label === timerLabelFromQuery)) {
     return timerLabelFromQuery;
   }
 
+  const storedLabel = resolveTimerLabelFromPresetId(storedPresetId);
+
+  if (storedLabel) {
+    return storedLabel;
+  }
+
   const recommendedLabel = resolveTimerLabelFromPresetId(recommendedPresetId);
 
   if (recommendedLabel) {
@@ -82,6 +141,7 @@ const resolveInitialTimerLabel = (timerLabelFromQuery: string | null, recommende
 
 export const SpaceWorkspaceWidget = () => {
   const searchParams = useSearchParams();
+  const storedSelection = useMemo(() => readStoredWorkspaceSelection(), []);
   const {
     thoughts,
     thoughtCount,
@@ -92,15 +152,17 @@ export const SpaceWorkspaceWidget = () => {
     setThoughtCompleted,
   } = useThoughtInbox();
 
-  const initialRoomId = resolveInitialRoomId(searchParams.get('room'));
+  const initialRoomId = resolveInitialRoomId(searchParams.get('room'), storedSelection.sceneId);
   const initialRoom = getRoomById(initialRoomId) ?? ROOM_THEMES[0];
   const initialGoal = searchParams.get('goal')?.trim() ?? '';
   const initialSoundPresetId = resolveInitialSoundPreset(
     searchParams.get('sound'),
+    storedSelection.soundPresetId,
     initialRoom.recommendedSoundPresetId,
   );
   const initialTimerLabel = resolveInitialTimerLabel(
     searchParams.get('timer'),
+    storedSelection.timerPresetId,
     initialRoom.recommendedTimerPresetId,
   );
 
@@ -109,7 +171,10 @@ export const SpaceWorkspaceWidget = () => {
   const [selectedTimerLabel, setSelectedTimerLabel] = useState(initialTimerLabel);
   const [goalInput, setGoalInput] = useState(initialGoal);
   const [selectedGoalId, setSelectedGoalId] = useState<string | null>(null);
-  const [selectionOverride, setSelectionOverride] = useState<SelectionOverride>({ sound: false, timer: false });
+  const [selectionOverride, setSelectionOverride] = useState<SelectionOverride>({
+    sound: Boolean(storedSelection.override?.sound),
+    timer: Boolean(storedSelection.override?.timer),
+  });
 
   const {
     selectedPresetId,
@@ -258,6 +323,24 @@ export const SpaceWorkspaceWidget = () => {
     };
   }, []);
 
+  useEffect(() => {
+    if (typeof window === 'undefined') {
+      return;
+    }
+
+    const timerPresetId = resolveTimerPresetIdFromLabel(selectedTimerLabel);
+
+    window.localStorage.setItem(
+      WORKSPACE_SELECTION_STORAGE_KEY,
+      JSON.stringify({
+        sceneId: selectedRoomId,
+        timerPresetId,
+        soundPresetId: selectedPresetId,
+        override: selectionOverride,
+      }),
+    );
+  }, [selectedRoomId, selectedTimerLabel, selectedPresetId, selectionOverride]);
+
   return (
     <div className="relative h-dvh overflow-hidden text-white">
       <div