docs(integration): correct channel claim and flag UDP port collision (#21)

SpaceGame's v1.0.0 evaluation (SpaceGame docs/rendezvous-eval.md @ 8eb5607) found the pilot doc asserting ChannelsCount=3 as current SpaceGame fact — their source uses LiteNetLib's single-channel default, and a peer mismatch fails connections silently, so the doc now states the requirement as agreement rather than a count. The compose file also gains a loud warning that host UDP 9050 collides with common game-client defaults during same-machine evaluation.

deploy/compose/compose.yaml

@@ -34,4 +34,8 @@ services:
       - ${RENDEZVOUS_SECRET_SOURCE:-./secrets/signing-key}:/run/secrets/rendezvous-signing-key:ro
     ports:
       - "127.0.0.1:${RENDEZVOUS_HTTP_HOST_PORT:-8080}:8080/tcp"
+      # 9050 is also a common game-client default UDP port. Evaluating this
+      # service on the same machine as a running game client can silently
+      # collide; remap with RENDEZVOUS_UDP_HOST_PORT and keep the advertised
+      # Rendezvous:Deployment:PublicUdpPort in appsettings matched to it.
       - "${RENDEZVOUS_UDP_HOST_PORT:-9050}:9050/udp"

docs/integration/spacegame-pilot.md

@@ -31,8 +31,11 @@ must be repeated from the public feed.
 
 ## Proven local path
 
-The SpaceGame host and client each create one caller-owned `NetManager`, set its
-three gameplay QoS channels before `Start`, and give the same manager and
+The SpaceGame host and client each create one caller-owned `NetManager`,
+configure any additional gameplay QoS channels before `Start` (the pilot
+harness used three; current SpaceGame source uses LiteNetLib's default single
+channel — both peers must simply agree, because a `ChannelsCount` mismatch
+fails the connection silently), and give the same manager and
 `RendezvousNetListener` to the coordinator. Rendezvous authenticates discovery,
 join authorization, host presence, mediation, and connection outcome reporting.
 After traversal, SpaceGame performs a separate audience-bound admission exchange