refactor: remove unused streamToUint8Array helper

The streamToUint8Array helper in src/node/runtime/streamUtils.ts had zero
references anywhere in the repository (verified via git grep across all
tracked files). It was orphaned after the experimental image-editing tool
work (#3282) that introduced it. Removing it is behavior-preserving: the
function uses only global APIs, so no imports needed cleanup, and the
file's other exports (shescape, streamToString) are unaffected.

Author: mux-bot

src/node/runtime/streamUtils.ts

@@ -43,47 +43,3 @@ export async function streamToString(stream: ReadableStream<Uint8Array>): Promis
     reader.releaseLock();
   }
 }
-
-/** Convert a ReadableStream<Uint8Array> to one concatenated Uint8Array. */
-export async function streamToUint8Array(
-  stream: ReadableStream<Uint8Array>,
-  maxBytes?: number
-): Promise<Uint8Array> {
-  const reader = stream.getReader();
-  const chunks: Uint8Array[] = [];
-  let totalLength = 0;
-
-  let completed = false;
-  try {
-    while (true) {
-      const { done, value } = await reader.read();
-      if (done) {
-        completed = true;
-        break;
-      }
-      const nextLength = totalLength + value.length;
-      if (maxBytes != null && nextLength > maxBytes) {
-        throw new Error(`Stream exceeded ${maxBytes} byte limit`);
-      }
-      chunks.push(value);
-      totalLength = nextLength;
-    }
-  } finally {
-    if (!completed) {
-      try {
-        await reader.cancel();
-      } catch {
-        // Stream may already be errored or canceled.
-      }
-    }
-    reader.releaseLock();
-  }
-
-  const output = new Uint8Array(totalLength);
-  let offset = 0;
-  for (const chunk of chunks) {
-    output.set(chunk, offset);
-    offset += chunk.length;
-  }
-  return output;
-}