accesslog-shipper: emit __shipstat__ sent-line checkpoints for splits reconciliation

The splits completeness floor is TIME-based (trust hours complete since shipper
connect) and blind to event-loss-by-rotation (2026-07-10: raw_events rotated
every 1-2min, cruncher lost ~85% of us-32 events, floor still called the hours
complete). Shipper now injects {"__shipstat__":1,"sess":..,"sent":N,"ts":..}
every 1000 lines or 30s through the SAME tcp pipe. Cruncher diffs shipper-sent
vs DB-ingested per gateway/hour -> a reconciliation-based floor that catches the
loss a clock cannot. sess=connection-start epoch so resets on reconnect are
detectable. Logic in a mounted .awk file (not inline) to dodge sh/awk quoting.
Verified on busybox:1.36 (systime/fflush OK). NOT deployed until claude@'s
cruncher filters __shipstat__ from event parsing - coordinating via SIP.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

drpc.yml

@@ -11,9 +11,14 @@ services:
     restart: unless-stopped
     volumes:
       - ./dshackle_logs:/logs:ro
+      # sent-line counter: injects __shipstat__ checkpoints into the stream so
+      # the listener cruncher can reconcile shipped-vs-ingested per gateway/hour
+      # (fixes the time-based completeness floor being blind to event-loss-by-
+      # rotation, 2026-07-10). Cruncher MUST filter __shipstat__ from events.
+      - ./accesslog-shipper.awk:/shipper.awk:ro
     command: >-
       sh -c 'while true; do
-      tail -F /logs/access_log.jsonl 2>/dev/null | nc ${SPLITS_LISTENER_HOST:-78.47.193.225} ${SPLITS_LISTENER_PORT:-9102};
+      tail -F /logs/access_log.jsonl 2>/dev/null | awk -f /shipper.awk | nc ${SPLITS_LISTENER_HOST:-78.47.193.225} ${SPLITS_LISTENER_PORT:-9102};
       echo shipper lost listener connection, retrying in 10s;
       sleep 10; done'