scrypted: HTTP keep-alive via node:http Agent + bump JPEG quality 2→1

Two changes in one commit because the keep-alive refactor reshapes
the fetch surface and the quality bump piggybacks naturally on it.

#1 — Keep-alive
ScryptedViewportProvider now uses node:http (always available, no
require sandbox dance like undici) with a per-host Agent:
  keepAlive: true, keepAliveMsecs: 30s, maxSockets: 2.
Pool size 2 matches the firmware's two-socket pipelining capacity
so frame N+1 can begin uploading on socket B while frame N is still
being decoded on socket A. Reusing the socket skips the SYN+SYN-ACK+
ACK round-trip on every POST — on a quiet LAN that's ~1ms saved per
frame, and far more on the p95 tail where TCP slow-start was driving
26-35ms net_up spikes in the measured data.

httpRequest() wraps http.request to expose tHeaders + tDone (so we
keep the existing per-stage script-side timing intact) and returns
{ status, headers, tHeaders, tDone }. Both pushStreamFrame and
postJSON migrated. The remaining fetch() calls (GET /state, GET
/config from the UI, and the one-shot snapshot POST) are non-hot
paths — left as fetch for now.

#2 — JPEG quality
ffmpeg -q:v 2 was the de facto "visually lossless" setting in earlier
notes; bumping to -q:v 1 squeezes one more notch of quality out of
the mjpeg encoder. JPEG size grows ~10-15%; with NODELAY landed and
fw_recv at ~22ms for 128KB we have plenty of headroom for the bigger
bodies. Applied to both the live-stream encoder and the one-shot
snapshot encoder.

0 files changed, 0 insertions, 0 deletions