Initialize initConsoleLogCapture() via Next.js instrumentation register()
hook so logs are captured from startup in headless/Docker deployments, and
add X-Accel-Buffering/Cache-Control headers to the SSE stream route to
prevent reverse proxies from buffering the initial payload.
The ReadableStream cancel() callback is not reliably invoked on client
disconnect under Next.js, causing emitter listeners (line/clear) and the
keepalive interval to accumulate, eventually triggering
MaxListenersExceededWarning.
Use request.signal as the primary disconnect trigger, with cancel() and
enqueue failures as fallbacks. Cleanup is idempotent via state.closed.
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
