cleanup phase 1: stale-comment refresh, zero behavior change

Removes/rewrites every comment that referenced the dead HTTP-streaming
architecture so a reader of v1.0.0+ source isn't chasing a model
that's been gone for several releases. No code paths changed; this is
the safe pre-pass before Phase 2's actual deletions.

Firmware (main/http_api.c):
- s_last_painted_seq / s_last_post_us / X-Frame-Seq parse / stale-
  frame guard / Server-Timing emission / TCP_NODELAY setsockopt /
  max_open_sockets=4 — each block now leads with "(Legacy from the
  HTTP-streaming era; removed in Phase 2)" so the reader knows the
  block is doomed, not load-bearing.
- /frame dim-mismatch comment narrowed: panel-native is always 800x480
  BGR888, no Scrypted-side variation expected; Scrypted does the
  rotation+scale via sharp/mediaManager/ffmpeg cascade (snapshot) or
  ffmpeg -vf (stream).
- "Single in-flight frame. Concurrent posts get 503" rewritten to
  reflect: decoder mutex now mostly serves to fence /frame snapshots
  against an active stream_server decode.

Firmware (main/stream_server.c:136-142):
- FIONREAD-skip rationale reduced from a 7-line paragraph to one
  sentence; the savings/tradeoff math now lives in the plan, not the
  per-line comment.

Script (scrypted/scrypted-viewport.ts):
- Top-of-file tuning constants block drops the "frame_interval_ms
  removed", "fps filter", "in-flight back-to-back startStream"
  rationale; one short line covers the model: "Stream rate is paced
  by camera + TCP backpressure; no app-level fps cap."
- agentFor() rationale rewritten: this Agent is over-engineered for
  control-plane traffic (~1 POST/min steady state) — a legacy of when
  it backed per-frame /frame POSTs. Marked for Phase 2 retirement.
- noDelay on Agent: clarified it's now a no-op safety for control
  plane (was load-bearing for live-stream pipelining).
- snapshot fire-and-forget comment: replaced X-Frame-Seq-race
  rationale with the actual TCP-streaming truth (sharp/mediaManager/
  ffmpeg cascade race against stream socket bring-up).
- writeLatencies probe: rewrote the "keep-alive socket" comment
  (live stream uses raw net.Socket, not the http.Agent pool).
- socketBackpressured: explicit "diagnostic only, never gates writes"
  comment added at declaration site.
- skipLogger header: rewrote the inFlight/MAX_INFLIGHT/fps-filter
  rationale into a one-line description of what the log line actually
  emits today.
- frameSeq map: now flagged as legacy of HTTP-streaming era, retired
  in Phase 2.

0 files changed, 0 insertions, 0 deletions