refactor(plugin-sdk): drop unrepresentable 101 from null-body set

Greptile: the Response constructor rejects status 101 by range, so listing
it in NULL_BODY_STATUSES suggested support the shim cannot provide. Keep
the set to 204/205/304 and explain the 101 exclusion in the comment.

packages/plugins/sdk/src/worker-rpc-host.ts

@@ -242,11 +242,12 @@ function canonicalize(value: unknown): string {
 }
 
 /**
- * Statuses the Fetch spec defines as null-body. The `Response` constructor
- * throws "Invalid response status code" when one of them carries a body, so
- * the http.fetch shim must rebuild them with an explicit `null` body.
+ * Null-body statuses the `Response` constructor can represent (the Fetch
+ * spec also defines 101, but the constructor rejects it by status range).
+ * The constructor throws "Invalid response status code" when one of these
+ * carries a body, so the http.fetch shim rebuilds them with `null` instead.
  */
-const NULL_BODY_STATUSES: ReadonlySet<number> = new Set([101, 204, 205, 304]);
+const NULL_BODY_STATUSES: ReadonlySet<number> = new Set([204, 205, 304]);
 
 export function isWorkerEntrypoint(entry: string, moduleUrl: string): boolean {
   const thisFile = realpathOrResolvedPath(fileURLToPath(moduleUrl));
@@ -617,10 +618,10 @@ export function startWorkerRpcHost(options: WorkerRpcHostOptions): WorkerRpcHost
           });
 
           // Reconstruct a Response-like object from the serialized result.
-          // The Fetch spec forbids a body on null-body statuses (101, 204,
-          // 205, 304), so `new Response("")` would throw for a successful
-          // 204 No Content and the plugin would report a landed write as
-          // failed. Pass `null` for those statuses, matching global fetch.
+          // The Fetch spec forbids a body on null-body statuses, so
+          // `new Response("")` would throw for a successful 204 No Content
+          // and the plugin would report a landed write as failed. Pass
+          // `null` for those statuses, matching global fetch.
           return new Response(NULL_BODY_STATUSES.has(result.status) ? null : result.body ?? null, {
             status: result.status,
             statusText: result.statusText,

packages/plugins/sdk/tests/worker-rpc-host.test.ts

@@ -1102,8 +1102,8 @@ describe("worker duplex channel dispatch", () => {
 describe("worker http.fetch response rebuild", () => {
   // The host serializes the upstream reply as
   // `{ status, statusText, headers, body }`. The worker rebuilds a `Response`
-  // from those fields. The Fetch spec forbids a body on null-body statuses
-  // (101, 204, 205, 304), so a plain `new Response(body)` throws for a
+  // from those fields. The Fetch spec forbids a body on null-body
+  // statuses (204, 205, 304), so a plain `new Response(body)` throws for a
   // successful 204 No Content and the plugin reports a landed write as failed.
   // The shim must drop the serialized body for those statuses, matching what
   // global `fetch` returns for the same upstream reply.