feat: detect first-run terminal theme (#5385)

packages/coding-agent/src/cli/startup-ui.ts

@@ -10,7 +10,7 @@ import {
 	FirstTimeSetupComponent,
 	type FirstTimeSetupResult,
 } from "../modes/interactive/components/first-time-setup.ts";
-import { detectTerminalBackground, initTheme, setTheme } from "../modes/interactive/theme/theme.ts";
+import { detectTerminalBackgroundTheme, initTheme, setTheme } from "../modes/interactive/theme/theme.ts";
 
 const OFFICIAL_PACKAGE_NAME = "@earendil-works/pi-coding-agent";
 const OFFICIAL_APP_NAME = "pi";
@@ -123,19 +123,25 @@ export async function showFirstTimeSetup(settingsManager: SettingsManager): Prom
 			resolve();
 		};
 
-		const component = new FirstTimeSetupComponent({
-			detectedTheme: detectTerminalBackground().theme,
-			onThemePreview: (themeName) => {
-				setTheme(themeName);
-				ui.invalidate();
-				ui.requestRender();
-			},
-			onSubmit: (result) => void finish(result),
-			onCancel: () => void finish(undefined),
-		});
-		ui.addChild(component);
-		ui.setFocus(component);
-		ui.start();
+		const showSetup = async () => {
+			ui.start();
+			const detection = await detectTerminalBackgroundTheme({ ui, timeoutMs: 100 });
+			setTheme(detection.theme);
+			const component = new FirstTimeSetupComponent({
+				detectedTheme: detection.theme,
+				onThemePreview: (themeName) => {
+					setTheme(themeName);
+					ui.requestRender();
+				},
+				onSubmit: (result) => void finish(result),
+				onCancel: () => void finish(undefined),
+			});
+			ui.addChild(component);
+			ui.setFocus(component);
+			ui.requestRender();
+		};
+
+		void showSetup();
 	});
 }