feat: add LogoManagementModal component for logo upload and management

components/BannerManagementModal.tsx

@@ -131,6 +131,61 @@ const BannerManagementModal: React.FC<BannerManagementModalProps> = ({
             </p>
           </div>
 
+          {/* File Upload */}
+          <div className="mb-6">
+            <h4 className="font-semibold text-textMain mb-3">Oder Bild hochladen</h4>
+            <div className="border-2 border-dashed border-border rounded-lg p-6 text-center hover:border-accentInfo/50 transition-colors">
+              <input
+                type="file"
+                accept="image/*"
+                onChange={async (e) => {
+                  const file = e.target.files?.[0];
+                  if (!file) return;
+
+                  const formData = new FormData();
+                  formData.append('banner', file);
+
+                  try {
+                    setLoading(true);
+                    setError(null);
+
+                    const response = await fetch(`https://vollidioten.ceraticsoft.de/api/projects/${projectId}/banner/upload`, {
+                      method: 'POST',
+                      credentials: 'include',
+                      body: formData
+                    });
+
+                    if (response.ok) {
+                      const data = await response.json();
+                      setBannerUrl(data.bannerUrl);
+                      onUpdate();
+                      onClose();
+                    } else {
+                      const errorData = await response.json();
+                      setError(errorData.error || 'Fehler beim Hochladen');
+                    }
+                  } catch (err) {
+                    console.error('Error uploading banner:', err);
+                    setError('Netzwerkfehler beim Hochladen');
+                  } finally {
+                    setLoading(false);
+                  }
+                }}
+                className="hidden"
+                id="banner-upload"
+              />
+              <label htmlFor="banner-upload" className="cursor-pointer">
+                <div className="w-12 h-12 mx-auto mb-4 bg-surfaceHighlight rounded-full flex items-center justify-center">
+                  <svg className="w-6 h-6 text-accentInfo" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M7 16a4 4 0 01-.88-7.903A5 5 0 1115.9 6L16 6a5 5 0 011 9.9M15 13l-3-3m0 0l-3 3m3-3v12" />
+                  </svg>
+                </div>
+                <p className="text-sm text-textMain font-medium">Bild auswählen</p>
+                <p className="text-xs text-textMuted mt-1">Max. 10MB, nur Bilddateien</p>
+              </label>
+            </div>
+          </div>
+
           {/* Preview */}
           {bannerUrl && bannerUrl !== currentBannerUrl && (
             <div className="mb-6">