fix list and improve cloud functions

functions/src/cover.js

@@ -21,7 +21,11 @@ async function performCoverGeneration(project) {
   let coverUrl = "";
   try {
     // Utiliser une taille fixe de 1024 pixels
-    coverUrl = await generateImageV2(prompt, 1024);
+    coverUrl = await generateImageV2(
+      prompt,
+      1024,
+      `users/${project.userId}/projects/${project.id}/generated-${Date.now()}.png`,
+    );
     console.log("coverUrl", coverUrl);
   } catch (e) {
     logger.error("❌ [Cover] generateImageV2 failed", {
@@ -73,7 +77,11 @@ async function performCombineGeneration(project) {
     fgPreview: String(foreground).slice(0, 80),
   });
 
-  const combinedUrl = await CombineCoverAndPicture(background, foreground);
+  const combinedUrl = await CombineCoverAndPicture(
+    background,
+    foreground,
+    `users/${project.userId}/projects/${project.id}/combine-${Date.now()}.png`,
+  );
 
   // Sauvegarder le résultat et marquer comme généré
   await db