story-kit: merge 195_story_preserve_newlines_in_chat_message_submission

frontend/src/components/MessageItem.test.tsx

@@ -59,6 +59,24 @@ describe("MessageItem component (Story 178 AC3)", () => {
 		expect(screen.getByText("Read(src/main.rs)")).toBeInTheDocument();
 	});
 
+	it("user messages use pre-wrap whitespace to preserve newlines (Story 195)", () => {
+		const { container } = render(
+			<MessageItem
+				msg={{ role: "user", content: "First line\nSecond line" }}
+			/>,
+		);
+
+		// The bubble div wrapping user text must have white-space: pre-wrap
+		// so newlines are rendered as visual line breaks
+		const divs = Array.from(container.querySelectorAll("div"));
+		const bubble = divs.find(
+			(div) =>
+				div.style.whiteSpace === "pre-wrap" &&
+				div.textContent?.includes("First line"),
+		);
+		expect(bubble).toBeDefined();
+	});
+
 	it("is wrapped in React.memo (has displayName or $$typeof memo)", () => {
 		// React.memo wraps the component — verify the export is memoized
 		// by checking that the component has a memo wrapper