refactor: reorganize imports and improve error handling across components

frontend/src/context/ThemeContextValue.ts

@@ -0,0 +1,10 @@
+import { createContext } from 'react'
+
+export type Theme = 'dark' | 'light'
+
+export interface ThemeContextType {
+  theme: Theme
+  toggleTheme: () => void
+}
+
+export const ThemeContext = createContext<ThemeContextType | undefined>(undefined)