Added registration and settings page

src/context/PreferencesContext.jsx

@@ -0,0 +1,47 @@
+import {createContext, useContext, useEffect, useState} from 'react';
+import {useTranslation} from 'react-i18next';
+
+const DARK_MODE_STORAGE_KEY = 'tbp_dark_mode';
+
+const PreferencesContext = createContext(null);
+
+export function PreferencesProvider({children}) {
+    const {i18n} = useTranslation();
+
+    const [isDarkMode, setIsDarkMode] = useState(() => {
+        const stored = localStorage.getItem(DARK_MODE_STORAGE_KEY);
+        return stored === null ? true : stored === 'true';
+    });
+
+    useEffect(() => {
+        if (isDarkMode) {
+            document.documentElement.classList.add('dark');
+        } else {
+            document.documentElement.classList.remove('dark');
+        }
+        localStorage.setItem(DARK_MODE_STORAGE_KEY, String(isDarkMode));
+    }, [isDarkMode]);
+
+    const setLanguage = (lang) => i18n.changeLanguage(lang);
+
+    return (
+        <PreferencesContext.Provider
+            value={{
+                isDarkMode,
+                setDarkMode: setIsDarkMode,
+                language: i18n.language,
+                setLanguage,
+            }}
+        >
+            {children}
+        </PreferencesContext.Provider>
+    );
+}
+
+export function usePreferences() {
+    const ctx = useContext(PreferencesContext);
+    if (!ctx) {
+        throw new Error('usePreferences must be used inside <PreferencesProvider>');
+    }
+    return ctx;
+}