nits: remove dead comment & align test style on local idioms

Author: ochafik

src/client/sse.ts

@@ -220,8 +220,6 @@ export class SSEClientTransport implements Transport {
 
     try {
       const commonHeaders = await this._commonHeaders();
-      // Note: this._requestInit?.headers already set in _commonHeaders
-      // const headers = new Headers({ ...commonHeaders, ...this._requestInit?.headers });
       const headers = new Headers(commonHeaders);
       headers.set("content-type", "application/json");
       const init = {

src/client/streamableHttp.ts

@@ -174,7 +174,7 @@ export class StreamableHTTPClientTransport implements Transport {
     if (this._sessionId) {
       headers["mcp-session-id"] = this._sessionId;
     }
-    if (this.protocolVersion != null) {
+    if (this.protocolVersion) {
       headers["mcp-protocol-version"] = this.protocolVersion;
     }