fix(site/src/pages/AgentsPage): remove stale NoDiffUrl story (#23306)

site/src/pages/AgentsPage/AgentDetail.stories.tsx

@@ -211,7 +211,9 @@ const meta: Meta<typeof AgentDetailLayout> = {
 		}),
 	},
 	beforeEach: () => {
+		localStorage.removeItem(RIGHT_PANEL_OPEN_KEY);
 		spyOn(API, "getApiKey").mockRejectedValue(new Error("missing API key"));
+		return () => localStorage.removeItem(RIGHT_PANEL_OPEN_KEY);
 	},
 };
 
@@ -588,22 +590,6 @@ export const CompletedWithDiffPanel: Story = {
 	},
 };
 
-/** Right panel stays closed when no diff-status URL exists. */
-export const NoDiffUrl: Story = {
-	parameters: {
-		queries: buildQueries(
-			{
-				id: CHAT_ID,
-				...baseChatFields,
-				title: "No diff yet",
-				status: "completed",
-			},
-			{ messages: [], queued_messages: [], has_more: false },
-			{ diffUrl: undefined },
-		),
-	},
-};
-
 /** Subagent tool-call/result messages render subagent cards. */
 export const WithSubagentCards: Story = {
 	parameters: {