feat(resume): 지난 한 조각 이어서 시작하는 진입 플로우 추가

맥락:
- /space 재진입 시 마지막 목표를 다시 쓰게 되어 시작 마찰이 컸다.
- work.md 작업 2 요구사항에 맞춰 목표 기반 Resume CTA를 진입 의식 안에 추가했다.

변경사항:
- workspace localStorage 스키마에 goal 필드를 추가하고 저장/복원에 반영했다.
- Setup Ritual에 지난 한 조각 이어서 블록을 추가했다.
- 이어서 시작은 저장 목표로 즉시 Focus 전환, 새로 시작은 목표 초기화 후 새 세션 입력으로 전환하도록 연결했다.
- session 문서 docs/session_brief.md, docs/90_current_state.md를 최신 상태로 갱신했다.

검증:
- npx tsc --noEmit

세션-상태: Resume CTA와 목표 복원 흐름이 /space 진입에 반영됨
세션-다음: Goal Complete 루프와 Recover(Notes→Inbox) 플로우 마감
세션-리스크: localStorage 기반 복원이라 다중 탭/스토리지 초기화 시 세션 연속성이 약할 수 있음

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

@@ -31,6 +31,7 @@ interface StoredWorkspaceSelection {
   sceneId?: string;
   timerPresetId?: string;
   soundPresetId?: string;
+  goal?: string;
   override?: Partial<SelectionOverride>;
 }
 
@@ -143,6 +144,13 @@ const resolveInitialTimerLabel = (
 export const SpaceWorkspaceWidget = () => {
   const searchParams = useSearchParams();
   const storedSelection = useMemo(() => readStoredWorkspaceSelection(), []);
+  const roomQuery = searchParams.get('room');
+  const goalQuery = searchParams.get('goal');
+  const soundQuery = searchParams.get('sound');
+  const timerQuery = searchParams.get('timer');
+  const storedGoal = storedSelection.goal?.trim() ?? '';
+  const hasQueryOverrides = Boolean(roomQuery || goalQuery || soundQuery || timerQuery);
+  const canOfferResume = storedGoal.length > 0 && !hasQueryOverrides;
   const {
     thoughts,
     thoughtCount,
@@ -154,16 +162,16 @@ export const SpaceWorkspaceWidget = () => {
     setThoughtCompleted,
   } = useThoughtInbox();
 
-  const initialRoomId = resolveInitialRoomId(searchParams.get('room'), storedSelection.sceneId);
+  const initialRoomId = resolveInitialRoomId(roomQuery, storedSelection.sceneId);
   const initialRoom = getRoomById(initialRoomId) ?? ROOM_THEMES[0];
-  const initialGoal = searchParams.get('goal')?.trim() ?? '';
+  const initialGoal = goalQuery?.trim() ?? '';
   const initialSoundPresetId = resolveInitialSoundPreset(
-    searchParams.get('sound'),
+    soundQuery,
     storedSelection.soundPresetId,
     initialRoom.recommendedSoundPresetId,
   );
   const initialTimerLabel = resolveInitialTimerLabel(
-    searchParams.get('timer'),
+    timerQuery,
     storedSelection.timerPresetId,
     initialRoom.recommendedTimerPresetId,
   );
@@ -173,6 +181,7 @@ export const SpaceWorkspaceWidget = () => {
   const [selectedTimerLabel, setSelectedTimerLabel] = useState(initialTimerLabel);
   const [goalInput, setGoalInput] = useState(initialGoal);
   const [selectedGoalId, setSelectedGoalId] = useState<string | null>(null);
+  const [showResumePrompt, setShowResumePrompt] = useState(canOfferResume);
   const [selectionOverride, setSelectionOverride] = useState<SelectionOverride>({
     sound: Boolean(storedSelection.override?.sound),
     timer: Boolean(storedSelection.override?.timer),
@@ -266,11 +275,16 @@ export const SpaceWorkspaceWidget = () => {
   };
 
   const handleGoalChipSelect = (chip: GoalChip) => {
+    setShowResumePrompt(false);
     setSelectedGoalId(chip.id);
     setGoalInput(chip.label);
   };
 
   const handleGoalChange = (value: string) => {
+    if (showResumePrompt) {
+      setShowResumePrompt(false);
+    }
+
     setGoalInput(value);
 
     if (value.trim().length === 0) {
@@ -283,6 +297,7 @@ export const SpaceWorkspaceWidget = () => {
       return;
     }
 
+    setShowResumePrompt(false);
     setWorkspaceMode('focus');
   };
 
@@ -309,6 +324,11 @@ export const SpaceWorkspaceWidget = () => {
     }
 
     const timerPresetId = resolveTimerPresetIdFromLabel(selectedTimerLabel);
+    const normalizedGoal = goalInput.trim().length > 0
+      ? goalInput.trim()
+      : showResumePrompt
+        ? storedGoal
+        : '';
 
     window.localStorage.setItem(
       WORKSPACE_SELECTION_STORAGE_KEY,
@@ -316,10 +336,11 @@ export const SpaceWorkspaceWidget = () => {
         sceneId: selectedRoomId,
         timerPresetId,
         soundPresetId: selectedPresetId,
+        goal: normalizedGoal,
         override: selectionOverride,
       }),
     );
-  }, [selectedRoomId, selectedTimerLabel, selectedPresetId, selectionOverride]);
+  }, [goalInput, selectedRoomId, selectedTimerLabel, selectedPresetId, selectionOverride, showResumePrompt, storedGoal]);
 
   return (
     <div className="relative h-dvh overflow-hidden text-white">
@@ -351,6 +372,24 @@ export const SpaceWorkspaceWidget = () => {
         onGoalChange={handleGoalChange}
         onGoalChipSelect={handleGoalChipSelect}
         onStart={handleStart}
+        resumeHint={
+          showResumePrompt
+            ? {
+              goal: storedGoal,
+              onResume: () => {
+                setGoalInput(storedGoal);
+                setSelectedGoalId(null);
+                setShowResumePrompt(false);
+                setWorkspaceMode('focus');
+              },
+              onStartFresh: () => {
+                setGoalInput('');
+                setSelectedGoalId(null);
+                setShowResumePrompt(false);
+              },
+            }
+            : undefined
+        }
       />
 
       <SpaceFocusHudWidget