feat(session): add Ctrl+N new-session shortcut

ui/src/App.test.tsx

@@ -135,6 +135,29 @@ describe("App command progress and errors", () => {
 		expect(status).toHaveTextContent("Ready for your next prompt");
 	});
 
+	it("starts a session in selected directory with Ctrl+N", async () => {
+		mocks.invoke.mockImplementation((command: string) => {
+			if (command === "create_session_runtime")
+				return Promise.resolve({ runtime: { runtimeId: "runtime-new" } });
+			return Promise.resolve(uiState);
+		});
+		render(<App />);
+		const event = new KeyboardEvent("keydown", {
+			bubbles: true,
+			cancelable: true,
+			ctrlKey: true,
+			key: "n",
+		});
+		window.dispatchEvent(event);
+
+		expect(event.defaultPrevented).toBe(true);
+		await waitFor(() =>
+			expect(mocks.invoke).toHaveBeenCalledWith("create_session_runtime", {
+				worktreePath: "/repo",
+			}),
+		);
+	});
+
 	it("loads categorized snapshot selectors and derives providers from choices", async () => {
 		const user = userEvent.setup();
 		const loaded: UiState = {

ui/src/App.tsx

@@ -320,10 +320,7 @@ export default function App() {
 					followUpProvider: followUpModel?.provider ?? "",
 					followUpModel: followUpModel?.modelId ?? "",
 					defaultThinkingLevel: selectedQuickModel
-						? reconcileThinkingLevel(
-								selectedQuickModel,
-								current.defaultThinkingLevel,
-							)
+						? reconcileThinkingLevel(selectedQuickModel, current.defaultThinkingLevel)
 						: current.defaultThinkingLevel,
 				};
 				if (
@@ -890,6 +887,25 @@ export default function App() {
 				entry.kind === "opening" ||
 				entry.kind === "listing"),
 	);
+	useEffect(() => {
+		const onKeyDown = (event: KeyboardEvent) => {
+			if (
+				event.defaultPrevented ||
+				event.repeat ||
+				!event.ctrlKey ||
+				event.metaKey ||
+				event.altKey ||
+				event.key.toLowerCase() !== "n" ||
+				sessionTabsBusy
+			)
+				return;
+			event.preventDefault();
+			void createRuntime();
+		};
+		window.addEventListener("keydown", onKeyDown);
+		return () => window.removeEventListener("keydown", onKeyDown);
+	}, [createRuntime, sessionTabsBusy]);
+
 	const closingRuntimeIds = new Set(
 		activeOperations
 			.filter((entry) => entry.kind === "closing" && entry.runtimeId)