fix: MapleStory 2 channel config — INSTANCED_CONTENT and port mapping

INSTANCED_CONTENT: "true" caused the game channel to register as
instanced (channelId=0), but FirstChannel() only returns non-instanced
channels, resulting in "server not found" on character select.

Changed to INSTANCED_CONTENT: "false" so channel registers as id=1.
Updated port mapping from 20002/21002 to 20003/21003 (base + channelId).
Added GRPC_LOGIN_IP env var to world service.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker/docker-compose.maple2.yml

@@ -52,6 +52,7 @@ services:
       - ../servers/maple2/.env
     environment:
       DB_IP: maple2-mysql
+      GRPC_LOGIN_IP: maple2-login
 
   maple2-login:
     build:
@@ -104,15 +105,15 @@ services:
       maple2-world:
         condition: service_started
     ports:
-      - "20002:20002"
-      - "21002:21002"
+      - "20003:20003"
+      - "21003:21003"
     env_file:
       - ../servers/maple2/.env
     environment:
       DB_IP: maple2-mysql
       GRPC_GAME_IP: maple2-game-ch0
       GRPC_WORLD_IP: maple2-world
-      INSTANCED_CONTENT: "true"
+      INSTANCED_CONTENT: "false"
 
 volumes:
   maple2_mysql: