Fix background task + socket in services + cleaning

mobile/traque-app/services/imageService.js

@@ -0,0 +1,32 @@
+// Constants
+import { SERVER_URL } from "../constants";
+
+export const uploadTeamImage = async (id, imageUri) => {
+    if (!imageUri || !id) return;
+
+    const data = new FormData();
+    data.append('file', {
+        uri: imageUri,
+        name: 'photo.jpg',
+        type: 'image/jpeg',
+    });
+
+    try {
+        const response = await fetch(`${SERVER_URL}/upload?team=${id}`, {
+            method: 'POST',
+            body: data,
+        });
+        
+        if (!response.ok) throw new Error("Échec de l'upload");
+        return await response.blob();
+    } catch (error) {
+        console.error("Erreur uploadImage :", error);
+        throw error;
+    }
+};
+
+export const enemyImage = (id) => {
+    if (!id) return require('../assets/images/missing_image.jpg');
+    
+    return {uri: `${SERVER_URL}/photo/enemy?team=${id}`};
+};