fix: persist agent scene generation pending state

components/agents/AgentGenerationWorkspaceDarkV2.tsx

@@ -527,9 +527,76 @@ function getReplacementCardStatusMeta(status: ReplacementCardStatus) {
 }
 
 interface LocalGenerationPendingState {
+  chatId: string;
   modeType: AgentGenerationResultModeType;
   expectedCount: number;
   userTurnCountAtStart: number;
+  timestamp: number;
+}
+
+const AGENT_PENDING_GENERATION_STORAGE_KEY = "ai-chatbot-agent-pending-generations";
+const AGENT_PENDING_GENERATION_EXPIRY_MS = 30 * 60 * 1000;
+
+function getStoredAgentPendingGenerations(): LocalGenerationPendingState[] {
+  if (typeof window === "undefined") {
+    return [];
+  }
+
+  try {
+    const raw = window.localStorage.getItem(AGENT_PENDING_GENERATION_STORAGE_KEY);
+    if (!raw) {
+      return [];
+    }
+
+    const now = Date.now();
+    const parsed = JSON.parse(raw);
+    if (!Array.isArray(parsed)) {
+      return [];
+    }
+
+    return parsed.filter((item) => {
+      if (!item || typeof item !== "object") {
+        return false;
+      }
+      const record = item as Record<string, unknown>;
+      const chatId = String(record.chatId || "").trim();
+      const modeType = String(record.modeType || "").trim();
+      const expectedCount = Number(record.expectedCount);
+      const userTurnCountAtStart = Number(record.userTurnCountAtStart);
+      const timestamp = Number(record.timestamp);
+      return (
+        Boolean(chatId) &&
+        (modeType === "scene_generation" ||
+          modeType === "detail_replacement" ||
+          modeType === "sku_replacement") &&
+        Number.isFinite(expectedCount) &&
+        expectedCount > 0 &&
+        Number.isFinite(userTurnCountAtStart) &&
+        Number.isFinite(timestamp) &&
+        now - timestamp < AGENT_PENDING_GENERATION_EXPIRY_MS
+      );
+    }) as LocalGenerationPendingState[];
+  } catch {
+    return [];
+  }
+}
+
+function saveStoredAgentPendingGenerations(items: LocalGenerationPendingState[]) {
+  if (typeof window === "undefined") {
+    return;
+  }
+
+  try {
+    window.localStorage.setItem(
+      AGENT_PENDING_GENERATION_STORAGE_KEY,
+      JSON.stringify(items)
+    );
+  } catch (error) {
+    console.warn(
+      "[AgentGenerationWorkspaceDarkV2] Failed to persist pending generation state:",
+      error
+    );
+  }
 }
 
 function AnimatedGenerationPlaceholderCard(params: {
@@ -693,6 +760,27 @@ export function AgentGenerationWorkspaceDarkV2({
   const [pendingGeneration, setPendingGeneration] =
     useState<LocalGenerationPendingState | null>(null);
 
+  useEffect(() => {
+    const restored = getStoredAgentPendingGenerations().find(
+      (item) => item.chatId === chatId
+    );
+    if (!restored) {
+      return;
+    }
+
+    setPendingGeneration((current) => current || restored);
+  }, [chatId]);
+
+  useEffect(() => {
+    const allItems = getStoredAgentPendingGenerations().filter(
+      (item) => item.chatId !== chatId
+    );
+    if (pendingGeneration) {
+      allItems.push(pendingGeneration);
+    }
+    saveStoredAgentPendingGenerations(allItems);
+  }, [chatId, pendingGeneration]);
+
   const { data: historyData } = useSWR<{ messages: ChatMessage[] }>(
     rawChatId ? `/api/messages?chatId=${rawChatId}` : null,
     fetcher,
@@ -1613,6 +1701,10 @@ export function AgentGenerationWorkspaceDarkV2({
       return;
     }
 
+    if (pendingGeneration.modeType === "scene_generation") {
+      return;
+    }
+
     if (!hasAssistantFailureAfterLastUser) {
       return;
     }
@@ -1911,6 +2003,7 @@ export function AgentGenerationWorkspaceDarkV2({
     setActiveResultModeType(currentResultModeType);
     setSelectedResultUrl(null);
     setPendingGeneration({
+      chatId,
       modeType: currentResultModeType,
       expectedCount:
         currentResultModeType === "scene_generation"
@@ -1919,6 +2012,7 @@ export function AgentGenerationWorkspaceDarkV2({
             ? detailReplacementReferenceCards.length
             : skuReplacementReferenceCards.length,
       userTurnCountAtStart: userMessageCount,
+      timestamp: Date.now(),
     });
     try {
       sendMessage({ role: "user", parts });