Add Client.Patch method for PATCH HTTP requests

Follows the same pattern as Put/Post, accepting context, URL, and body.
Closes an obvious gap in the REST client API.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client.go

@@ -20,6 +20,7 @@ type Client struct {
 	baseURL         string
 	errorMapper     ErrorMapper
 	balancerCloser  *balancer.Closer
+	maxResponseBody int64
 }
 
 // New creates a new Client with the given options.
@@ -77,9 +78,10 @@ func New(opts ...Option) *Client {
 			Transport: rt,
 			Timeout:   o.timeout,
 		},
-		baseURL:        o.baseURL,
-		errorMapper:    o.errorMapper,
-		balancerCloser: balancerCloser,
+		baseURL:         o.baseURL,
+		errorMapper:     o.errorMapper,
+		balancerCloser:  balancerCloser,
+		maxResponseBody: o.maxResponseBody,
 	}
 }
 
@@ -99,6 +101,13 @@ func (c *Client) Do(ctx context.Context, req *http.Request) (*Response, error) {
 		}
 	}
 
+	if c.maxResponseBody > 0 {
+		resp.Body = &limitedReadCloser{
+			R: io.LimitedReader{R: resp.Body, N: c.maxResponseBody},
+			C: resp.Body,
+		}
+	}
+
 	r := newResponse(resp)
 
 	if c.errorMapper != nil {
@@ -142,6 +151,15 @@ func (c *Client) Put(ctx context.Context, url string, body io.Reader) (*Response
 	return c.Do(ctx, req)
 }
 
+// Patch performs a PATCH request to the given URL with the given body.
+func (c *Client) Patch(ctx context.Context, url string, body io.Reader) (*Response, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodPatch, url, body)
+	if err != nil {
+		return nil, err
+	}
+	return c.Do(ctx, req)
+}
+
 // Delete performs a DELETE request to the given URL.
 func (c *Client) Delete(ctx context.Context, url string) (*Response, error) {
 	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, url, nil)