Ajoute le detail des erreurs Postal

server/postal.ts

@@ -55,9 +55,24 @@ export function createPostalClient(options: CreatePostalClientOptions): PostalCl
         })
       });
 
-      const payload = (await response.json().catch(() => null)) as { status?: string } | null;
+      const rawBody = await response.text().catch(() => "");
+      const payload =
+        rawBody.length > 0
+          ? (((() => {
+              try {
+                return JSON.parse(rawBody) as { status?: string; message?: string; error?: string };
+              } catch {
+                return null;
+              }
+            })()) ?? null)
+          : null;
       if (!response.ok || payload?.status !== "success") {
-        throw new Error(`postal_send_failed:${response.status}`);
+        const details =
+          payload?.error?.trim() ||
+          payload?.message?.trim() ||
+          rawBody.trim().slice(0, 500) ||
+          "no_response_body";
+        throw new Error(`postal_send_failed:${response.status}:${details}`);
       }
     }
   };