feat: Add EU cookie banner and user settings page

Cookie Banner:
- GDPR-compliant consent banner
- Shows on first visit, stores consent in localStorage
- Two options: Accept All / Only Essential
- Dark theme with smooth animations

Settings Page (/settings):
- Profile form: display name editing
- Password change with validation
- Cookie settings info section
- Privacy links and account info

New files:
- src/hooks/useCookieConsent.ts
- src/components/CookieBanner.tsx
- src/components/ProfileForm.tsx
- src/components/PasswordChangeForm.tsx
- src/services/profile-actions.ts
- src/app/settings/page.tsx

src/services/profile-actions.ts

@@ -0,0 +1,150 @@
+'use server';
+
+import { createClient } from '@/lib/supabase/server';
+import { revalidatePath } from 'next/cache';
+
+export interface ProfileUpdateResult {
+    success: boolean;
+    error?: string;
+}
+
+/**
+ * Update user profile (display_name, avatar_url)
+ */
+export async function updateProfile(formData: FormData): Promise<ProfileUpdateResult> {
+    const supabase = await createClient();
+
+    try {
+        const { data: { user } } = await supabase.auth.getUser();
+        if (!user) {
+            return { success: false, error: 'Nicht autorisiert' };
+        }
+
+        const displayName = formData.get('display_name') as string;
+
+        const { error } = await supabase
+            .from('profiles')
+            .upsert({
+                id: user.id,
+                display_name: displayName?.trim() || null,
+                updated_at: new Date().toISOString(),
+            });
+
+        if (error) {
+            console.error('[updateProfile] Error:', error);
+            return { success: false, error: error.message };
+        }
+
+        revalidatePath('/settings');
+        return { success: true };
+
+    } catch (error) {
+        console.error('[updateProfile] Error:', error);
+        return { success: false, error: 'Profil konnte nicht aktualisiert werden' };
+    }
+}
+
+/**
+ * Change user password
+ */
+export async function changePassword(formData: FormData): Promise<ProfileUpdateResult> {
+    const supabase = await createClient();
+
+    try {
+        const { data: { user } } = await supabase.auth.getUser();
+        if (!user) {
+            return { success: false, error: 'Nicht autorisiert' };
+        }
+
+        const newPassword = formData.get('new_password') as string;
+        const confirmPassword = formData.get('confirm_password') as string;
+
+        if (!newPassword || newPassword.length < 6) {
+            return { success: false, error: 'Passwort muss mindestens 6 Zeichen lang sein' };
+        }
+
+        if (newPassword !== confirmPassword) {
+            return { success: false, error: 'Passwörter stimmen nicht überein' };
+        }
+
+        const { error } = await supabase.auth.updateUser({
+            password: newPassword
+        });
+
+        if (error) {
+            console.error('[changePassword] Error:', error);
+            return { success: false, error: error.message };
+        }
+
+        return { success: true };
+
+    } catch (error) {
+        console.error('[changePassword] Error:', error);
+        return { success: false, error: 'Passwort konnte nicht geändert werden' };
+    }
+}
+
+/**
+ * Get user profile data
+ */
+export async function getProfile() {
+    const supabase = await createClient();
+
+    try {
+        const { data: { user } } = await supabase.auth.getUser();
+        if (!user) {
+            return null;
+        }
+
+        const { data: profile } = await supabase
+            .from('profiles')
+            .select('id, display_name, avatar_url, created_at, updated_at')
+            .eq('id', user.id)
+            .single();
+
+        return {
+            id: user.id,
+            email: user.email,
+            display_name: profile?.display_name || null,
+            avatar_url: profile?.avatar_url || null,
+            created_at: user.created_at,
+        };
+
+    } catch (error) {
+        console.error('[getProfile] Error:', error);
+        return null;
+    }
+}
+
+/**
+ * Delete user account (marks for deletion, doesn't immediately delete)
+ */
+export async function requestAccountDeletion(): Promise<ProfileUpdateResult> {
+    const supabase = await createClient();
+
+    try {
+        const { data: { user } } = await supabase.auth.getUser();
+        if (!user) {
+            return { success: false, error: 'Nicht autorisiert' };
+        }
+
+        // Mark profile for deletion (actual deletion handled separately)
+        const { error } = await supabase
+            .from('profiles')
+            .update({
+                deletion_requested_at: new Date().toISOString(),
+            })
+            .eq('id', user.id);
+
+        if (error) {
+            console.error('[requestAccountDeletion] Error:', error);
+            return { success: false, error: error.message };
+        }
+
+        return { success: true };
+
+    } catch (error) {
+        console.error('[requestAccountDeletion] Error:', error);
+        return { success: false, error: 'Löschanfrage konnte nicht erstellt werden' };
+    }
+}