[WRONG BRANCH] fix(responses): bound terminal SSE relay and restore Windows native passthrough

[luvs01]

Motivation

• Prevent reintroducing the Bun#32111 Windows crash by avoiding a JS pull wrapper for native passthrough SSE when the runtime/config gate keeps the legacy tee path.
• Prevent unbounded memory growth from delimiter-free or adversarial SSE frames by capping the client-side buffered frame size.
• Keep existing eager-relay behavior on runtimes that are known-fixed while protecting known-bad runtimes and the inspection paths.

Description

• Add a MAX_CLIENT_SSE_FRAME_BYTES cap (4 MiB) and enforce it in the terminal-aware SSE boundary (createSseTerminalOutputBoundary.feed) to throw and drop oversized partial frames instead of accumulating them in memory.
• Restore the native passthrough branch for Windows no-rewrite traffic so that when process.platform === "win32" && !needsClientRewrite the client branch remains the native Response body rather than being wrapped in relaySseWithFailedTail.
• Update the failed-tail and eager relay tests to cover the new frame-cap behavior and the Windows passthrough invariant.
• Minor test and assertion updates to reflect the enforced cap and expected abort/terminal behavior in both relay paths.

Testing

• Ran typecheck with bun x tsc --noEmit, which succeeded.
• Executed the focused test subset with the bundled baseline Bun: node_modules/@oven/bun-linux-x64-baseline/bin/bun test tests/sse-failed-tail.test.ts tests/relay-eager.test.ts tests/passthrough-abort.test.ts, and those tests passed (61 passed, 0 failed).
• Ran bun run privacy:scan, which passed; a full bun run test was attempted but unrelated management/API tests timed out or observed environment-specific failures and were therefore not used as verification for this focused security fix.

---

Codex Task

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.
To continue using code reviews, add credits to your account and enable them for code reviews in your settings.

[coderabbitai]

Warning

Review limit reached

@luvs01, you've reached your PR review limit, so we couldn't start this review.

Next review available in: 37 seconds

Enable usage-based reviews in Billing to review now. Otherwise, wait until the next included review is available.
You're only billed for reviews past your plan's rate limits ($0.25/file).

How can I continue?

After more reviews become available, a review can be triggered using the @coderabbitai review command as a PR comment. Alternatively, push new commits to this PR.

To avoid repeated limits, reduce automatic review volume by pausing incremental auto-reviews earlier, using label-based review opt-in, excluding WIP or generated PR titles, or requesting reviews manually when the PR is ready. If your team needs uninterrupted high-volume reviews, an organization admin can enable usage-based reviews.

How do review limits work?

CodeRabbit enforces per-developer PR review limits for each organization. Most developers receive the normal plan review availability.

For paid Pro and Pro+ PR reviews, CodeRabbit uses adaptive limits for sustained high-volume activity. When a developer's recent PR review activity reaches the 95th percentile or higher among CodeRabbit users, additional reviews become available more gradually as earlier reviews age out of the rolling window.

Please refer docs for additional details.

Review details

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: bf9aa774-021a-4461-af5b-d14e52228985

📥 Commits

Reviewing files that changed from the base of the PR and between 2468502 and d2c9c35.

📒 Files selected for processing (5)

• src/server/relay.ts
• src/server/responses/core.ts
• tests/passthrough-abort.test.ts
• tests/relay-eager.test.ts
• tests/sse-failed-tail.test.ts

---

_{Comment @coderabbitai help to get the list of available commands.}

[github-actions]

✅ Deterministic PR hygiene checks passed.

[github-actions]

⏳ DRAFT

• wrong target branch (main); retarget to dev.

What to do

• Retarget this PR to dev — all contributions go to dev.

Its title has been prefixed with [WRONG BRANCH].
This pull request is being kept as a draft automatically. Once every issue above is resolved, it will be marked ready for review again.