New UI (#157, #164)

- Add a react UI to replace the plain HTML one. 
- Serve as a foundation for better GUI interactions

ui/src/contexts/ThemeProvider.tsx

@@ -0,0 +1,33 @@
+import { createContext, useContext, useEffect, type ReactNode } from "react";
+import { usePersistentState } from "../hooks/usePersistentState";
+
+type ThemeContextType = {
+  isDarkMode: boolean;
+  toggleTheme: () => void;
+};
+
+const ThemeContext = createContext<ThemeContextType | undefined>(undefined);
+
+type ThemeProviderProps = {
+  children: ReactNode;
+};
+
+export function ThemeProvider({ children }: ThemeProviderProps) {
+  const [isDarkMode, setIsDarkMode] = usePersistentState<boolean>("theme", false);
+
+  useEffect(() => {
+    document.documentElement.setAttribute("data-theme", isDarkMode ? "dark" : "light");
+  }, [isDarkMode]);
+
+  const toggleTheme = () => setIsDarkMode((prev) => !prev);
+
+  return <ThemeContext.Provider value={{ isDarkMode, toggleTheme }}>{children}</ThemeContext.Provider>;
+}
+
+export function useTheme(): ThemeContextType {
+  const context = useContext(ThemeContext);
+  if (context === undefined) {
+    throw new Error("useTheme must be used within a ThemeProvider");
+  }
+  return context;
+}