feat: init sproutclaw-web — Go+Gin backend + React frontend

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/context/BootstrapContext.tsx

@@ -0,0 +1,89 @@
+import {
+	createContext,
+	useCallback,
+	useContext,
+	useEffect,
+	useMemo,
+	useRef,
+	useState,
+	type ReactNode,
+} from "react";
+import { useLocation } from "react-router-dom";
+import { SplashScreen } from "../components/pwa/SplashScreen";
+
+const MIN_SPLASH_MS = 400;
+const SKIP_SPLASH_KEY = "sproutclaw-warm-boot";
+
+type BootstrapRoute = "chat" | "settings";
+
+interface BootstrapContextValue {
+	markRouteReady: (route: BootstrapRoute) => void;
+}
+
+const BootstrapContext = createContext<BootstrapContextValue | null>(null);
+
+export function BootstrapProvider({ children }: { children: ReactNode }) {
+	const location = useLocation();
+	const route: BootstrapRoute = location.pathname.startsWith("/settings") ? "settings" : "chat";
+	const [readyRoutes, setReadyRoutes] = useState<Record<BootstrapRoute, boolean>>({
+		chat: false,
+		settings: false,
+	});
+	const [splashVisible, setSplashVisible] = useState(true);
+	const [splashExiting, setSplashExiting] = useState(false);
+	const mountTime = useRef(Date.now());
+
+	const markRouteReady = useCallback((readyRoute: BootstrapRoute) => {
+		setReadyRoutes((prev) => (prev[readyRoute] ? prev : { ...prev, [readyRoute]: true }));
+	}, []);
+
+	useEffect(() => {
+		setReadyRoutes((prev) => ({ ...prev, [route]: false }));
+		setSplashVisible(true);
+		setSplashExiting(false);
+		mountTime.current = Date.now();
+	}, [route]);
+
+	useEffect(() => {
+		if (!readyRoutes[route]) return;
+
+		let warmBoot = false;
+		try {
+			warmBoot = sessionStorage.getItem(SKIP_SPLASH_KEY) === "1";
+			sessionStorage.setItem(SKIP_SPLASH_KEY, "1");
+		} catch {
+			/* ignore */
+		}
+
+		if (warmBoot) {
+			setSplashVisible(false);
+			setSplashExiting(false);
+			return;
+		}
+
+		const elapsed = Date.now() - mountTime.current;
+		const remaining = Math.max(0, MIN_SPLASH_MS - elapsed);
+
+		const timer = window.setTimeout(() => {
+			setSplashExiting(true);
+			window.setTimeout(() => setSplashVisible(false), 420);
+		}, remaining);
+
+		return () => window.clearTimeout(timer);
+	}, [readyRoutes, route]);
+
+	const value = useMemo(() => ({ markRouteReady }), [markRouteReady]);
+
+	return (
+		<BootstrapContext.Provider value={value}>
+			{children}
+			{splashVisible ? <SplashScreen exiting={splashExiting} /> : null}
+		</BootstrapContext.Provider>
+	);
+}
+
+export function useBootstrap(): BootstrapContextValue {
+	const ctx = useContext(BootstrapContext);
+	if (!ctx) throw new Error("useBootstrap must be used within BootstrapProvider");
+	return ctx;
+}