fix: extend abort signal coverage through response body consumption

[Copilot]

fetchWithTimeout() in effect-operator-kit clears its abort timer the moment fetch() resolves with response headers. response.text() then runs unguarded — a server that sends headers immediately but stalls the body stream bypasses timeoutMs entirely.

Changes

• fetchWithPlainHeaders (both clients) — converted from a thin header-normalization shim to a full round-trip wrapper: awaits headers, then races response.text() against the same AbortSignal passed in via init. If the timer fires mid-body, the body-read Promise rejects with AbortError immediately, which the existing TransportError path surfaces as AdGuardUnreachableError / AdGuardSyncUnreachableError.

// Body read now races the signal that fetchWithTimeout already manages
const bodyText = await new Promise<string>((resolve, reject) => {
  const onAbort = () =>
    reject(Object.assign(new Error("The operation was aborted"), { name: "AbortError" }));
  signal?.addEventListener("abort", onAbort, { once: true });
  response.text().then(
    (text) => { signal?.removeEventListener("abort", onAbort); resolve(text); },
    (err)  => { signal?.removeEventListener("abort", onAbort); reject(err); },
  );
});
return new Response(bodyText, { status: response.status, headers: response.headers });

• Regression tests — added to client.test.ts and sync-client.test.ts: stub fetch to resolve headers instantly but never close the body stream; assert that timeoutMs causes the expected unreachable error rather than hanging indefinitely.

• Fixes regression: response-body stalls bypass request timeout #10

[Copilot]

Pull request overview

This PR fixes a timeout regression where request timeouts stopped applying once fetch() returned response headers, allowing stalled response bodies to hang indefinitely. It does so by ensuring the fetch wrapper does not resolve until the response body has been consumed (or the shared abort signal fires), and adds regression coverage for the “headers arrive, body stalls” scenario.

Changes:

• Update both clients’ fetchWithPlainHeaders to keep the upstream abort signal “in play” through response.text() (including canceling the body stream on abort).
• Add regression tests for both clients where fetch resolves headers immediately but the response body never completes.
• Add .graphtrail/ to .gitignore.

Note: I did not run ./scripts/verify in this review environment (no verification results to report).

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/adguard-client.ts	Wraps fetch to extend abort/timeout coverage through response body consumption.
src/adguard-sync-client.ts	Same timeout/body-consumption protection for the Sync client transport.
tests/client.test.ts	Adds regression test for “headers resolved, body stalls” timeout behavior.
tests/sync-client.test.ts	Adds the analogous stalled-body timeout regression test for the Sync client.
.gitignore	Ignores .graphtrail/.

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