Deliver an app's saved sends over HTTP, in order and in batches (083)

pure-serve --send OUTPUT=http://host:port/path wires an output: after
every save the owner queues the new sends as JSON (fields and groups)
and a thread per output posts them in order with X-Pure-Source,
X-Pure-Sequence and Idempotency-Key. A 2xx, or a Pure receiver's
refusal, delivers; the owner then trims. 408, 429, 5xx and no answer
are sent again after a pause growing to 10 s, other answers every 10 s:
nothing is dropped. A Pure receiver applies a delivered message with
pure_app_deliver (now taking placed fields) and advertises
X-Pure-Batch: 256; the sender then posts up to that many numbers in a
row as one JSON array (X-Pure-Count), applied in order in one burst
with one save.

Delivery kept up with orders once batched (391 deliveries/s one at a
time; a backlog of 20,000 went at 60k/s). With four clients ordering,
killing the receiver and then the sender (-9) left the receiver's count
and total equal to what the sender saved, five times and under ASan.

1 files changed, 2 insertions, 2 deletions

diff --git a/docs/research/078-app-connections.md b/docs/research/078-app-connections.md
index 5e89853..a75cdfd 100644
--- a/docs/research/078-app-connections.md
+++ b/docs/research/078-app-connections.md
@@ -2,8 +2,8 @@
 
 2026-09-26. 설계 노트이며 구현 순서를 포함한다. 상태: 1단계(Pure 런타임: 출력, `SEND`, outbox·inbox와 그 저장)와
 2단계(aup `output`·`send`)를 2026-09-27에 구현했다([008 앱 사이의 연결](../design/008-module-format.md)). 호스트의 배선과
-전달(3·4단계)은 [로드맵](../roadmap.md) 중기 1(외부로 나가는 호출)과 함께 한다. 외부 API 호출도 같은 outbox 위에 선다(출력을
-HTTP 끝점에 잇는 배선).
+전달은 한 프로세스 안이 아니라 곧바로 HTTP로 했다(`pure-serve --send`, [083](083-delivery-over-http.md)). 다른 앱에도 외부 API에도
+같은 outbox와 같은 전달이다.
 
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