feat: Implement cookie consent management with a new banner and introduce a language-aware root redirection.

frontend/src/contexts/CookieContext.tsx

@@ -0,0 +1,101 @@
+import React, { createContext, useContext, useEffect, useState } from 'react';
+
+export interface CookieConsent {
+    essential: boolean; // Always true
+    preferences: boolean; // Language, Theme
+    analytics: boolean; // Optional future use
+}
+
+interface CookieContextType {
+    consent: CookieConsent;
+    updateConsent: (newConsent: CookieConsent) => void;
+    acceptAll: () => void;
+    rejectAll: () => void;
+    hasInteracted: boolean; // True if user has made a choice
+    showBanner: boolean;
+    closeBanner: () => void;
+}
+
+const defaultConsent: CookieConsent = {
+    essential: true,
+    preferences: false,
+    analytics: false,
+};
+
+const CookieContext = createContext<CookieContextType | undefined>(undefined);
+
+export const CookieProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+    const [consent, setConsent] = useState<CookieConsent>(defaultConsent);
+    const [hasInteracted, setHasInteracted] = useState(false);
+    const [showBanner, setShowBanner] = useState(false);
+
+    useEffect(() => {
+        const savedConsent = localStorage.getItem('cookie_consent');
+        if (savedConsent) {
+            try {
+                const parsed = JSON.parse(savedConsent);
+                setConsent({ ...defaultConsent, ...parsed, essential: true });
+                setHasInteracted(true);
+                setShowBanner(false);
+            } catch (e) {
+                // Invalid json, treat as no consent
+                setShowBanner(true);
+            }
+        } else {
+            setShowBanner(true);
+        }
+    }, []);
+
+    const saveConsent = (newConsent: CookieConsent) => {
+        localStorage.setItem('cookie_consent', JSON.stringify(newConsent));
+        setConsent(newConsent);
+        setHasInteracted(true);
+        setShowBanner(false);
+    };
+
+    const updateConsent = (newConsent: CookieConsent) => {
+        saveConsent({ ...newConsent, essential: true });
+    };
+
+    const acceptAll = () => {
+        saveConsent({
+            essential: true,
+            preferences: true,
+            analytics: true,
+        });
+    };
+
+    const rejectAll = () => {
+        saveConsent({
+            essential: true,
+            preferences: false,
+            analytics: false,
+        });
+    };
+
+    const closeBanner = () => {
+        setShowBanner(false);
+    };
+
+    return (
+        <CookieContext.Provider value={{
+            consent,
+            updateConsent,
+            acceptAll,
+            rejectAll,
+            hasInteracted,
+            showBanner,
+            closeBanner
+        }}>
+            {children}
+        </CookieContext.Provider>
+    );
+};
+
+export const useCookie = () => {
+    const context = useContext(CookieContext);
+    if (!context) {
+        throw new Error('useCookie must be used within a CookieProvider');
+    }
+    return context;
+};