fix: stop retrying non-idempotent requests after a transport error

The status guard covered 429 and 5xx, but the catch branch still replayed
every method, so a consumed registerWebhook or token rotation could run
twice after a lost connection.

Claude-Session: https://claude.ai/code/session_01Agoc9bRVE9KL7mmWtey9Vq

src/client.ts

@@ -361,10 +361,11 @@ export class ElydoraClient {
           throw err;
         }
 
-        if (attempt < this.maxRetries) {
+        if (attempt < this.maxRetries && isIdempotent(method)) {
           await sleep(Math.min(1000 * 2 ** attempt, 10_000));
           continue;
         }
+        break;
       }
     }