Improves API client response handling and idempotency

Extends `X-Idempotency-Key` header usage to `DELETE` and `PUT` requests, ensuring idempotent behavior for a wider range of modifying API operations. Updates the documentation and client implementation for `DELETE` requests.

Refactors `handleResponse` to robustly parse API responses. It now reads the response body once as text, enabling graceful handling of non-JSON error bodies and consistent processing of successful or empty responses.

README.md

@@ -610,7 +610,7 @@ Her API isteğine (`login` ve `refresh` dahil) aşağıdaki header'lar eklenir:
 | `X-Signature` | hex string | HMAC-SHA256 imzası (bkz. aşağısı) |
 | `X-Timestamp` | `Date.now()` string | Unix epoch, milisaniye |
 | `X-Nonce` | UUID v4 | Her istekte tekil, replay saldırısı önleme |
-| `X-Idempotency-Key` | UUID v4 | Yalnızca `POST` ve `PATCH` isteklerinde |
+| `X-Idempotency-Key` | UUID v4 | `POST`, `PUT`, `PATCH` ve `DELETE` isteklerinde |
 
 ### HMAC-SHA256 İmza Hesabı
 
@@ -664,7 +664,7 @@ X-Signature = HMAC-SHA256(imzalanacak, secret) → "7be41d..."
 | `X-Signature` | ✅ | ✅ | ✅ |
 | `X-Timestamp` | ✅ | ✅ | ✅ |
 | `X-Nonce` | ✅ | ✅ | ✅ |
-| `X-Idempotency-Key` | ✅ | ✅ | ✅ (POST/PATCH) |
+| `X-Idempotency-Key` | ✅ | ✅ | ✅ (POST/PUT/PATCH/DELETE) |
 
 ### Güvenlik Önerileri
 

src/client.ts

@@ -40,14 +40,24 @@ async function buildHeaders(
 }
 
 async function handleResponse<T>(response: Response): Promise<T> {
+  const rawBody = await response.text();
+
   if (!response.ok) {
-    const error = await response.json().catch(() => ({}));
-    const msg = (error as { message?: string }).message ?? response.statusText;
+    let msg = response.statusText;
+    if (rawBody) {
+      try {
+        const error = JSON.parse(rawBody) as { message?: string };
+        msg = error.message ?? rawBody;
+      } catch {
+        msg = rawBody;
+      }
+    }
     throw new Error(`API error [${response.status}]: ${msg}`);
   }
-  // 204 No Content
-  if (response.status === 204) return {} as T;
-  return response.json() as Promise<T>;
+
+  if (!rawBody) return {} as T;
+
+  return JSON.parse(rawBody) as T;
 }
 
 export async function apiGet<T>(
@@ -98,7 +108,7 @@ export async function apiPatch<T>(
 }
 
 export async function apiDelete<T>(path: string): Promise<T> {
-  const headers = await buildHeaders("DELETE", path, "", false);
+  const headers = await buildHeaders("DELETE", path, "", true);
 
   const response = await fetch(`${config.baseUrl}${path}`, {
     method: "DELETE",