Function streamPresignedBody

src/commands/test.ts:7874–7924

* Stream a presigned URL into the Output's chunk writer using the * deps-provided fetch impl, with no API-key headers — presigned URLs * carry their own authority. Three failure shapes the caller might * see, all routed through the typed envelope so `index.ts` produces * the documented exit code

(url: string, out: Output, deps: TestDeps)

 * the reader may want to start indexing before the download finishes.
 */
async function streamPresignedBody(url: string, out: Output, deps: TestDeps): Promise<void> {
  const fetchImpl = deps.fetchImpl ?? globalThis.fetch.bind(globalThis);
  let response: Response;
  try {
    response = await fetchImpl(url);
  } catch (err) {
    const message = err instanceof Error ? err.message : String(err);
    throw new TransportError(`Failed to download presigned code body: ${message}`);
  }
  if (!response.ok) {
    throw ApiError.fromEnvelope({
      error: {
        code: 'UNAVAILABLE',
        message: `Failed to download presigned code body (HTTP ${response.status}).`,
        nextAction:
          'Re-run `testsprite test code get`. Presigned URLs expire after a short window.',
        requestId: 'local',
        details: { status: response.status, url },
      },
    });
  }
  if (!response.body) {
    // No streamable body (some test runtimes / fetch polyfills). Fall
    // back to text() — same correctness, just no streaming benefit.
    await out.writeChunk(await response.text());
    return;
  }
  const reader = response.body.getReader();
  const decoder = new TextDecoder();
  try {
    while (true) {
      const { value, done } = await reader.read();
      if (done) break;
      if (value && value.byteLength > 0) {
        // `await` is load-bearing: the default rawStdout writer
        // resolves on `'drain'` when stdout's kernel buffer is full,
        // which pauses this loop so we don't pull more chunks from
        // the network than the consumer can absorb.
        await out.writeChunk(decoder.decode(value, { stream: true }));
      }
    }
    // Flush any remaining buffered bytes from a multi-byte UTF-8 codepoint
    // straddling a chunk boundary. Without this the last code point of a
    // file ending in (say) a Chinese character would be silently dropped.
    const tail = decoder.decode();
    if (tail.length > 0) await out.writeChunk(tail);
  } catch (err) {
    const message = err instanceof Error ? err.message : String(err);
    throw new TransportError(`Failed mid-download of presigned code body: ${message}`);
  }
}

function renderTestListText(page: Page<CliTest>): string {
  if (page.items.length === 0) {