Rebrand welcome messages and re-enable drop-roll debug logging

Welcome message default/example changed from "Welcome to ROSE" to
"Welcome to ROSS", and the hardcoded post-login system message
replaced with a ROSS-specific credit line.

Also re-enable the codedebug SendPM lines in GetNewDrop that report
the raw randv/money/zulyrate/item/itemrate values behind each
zuly-vs-item roll (previously commented out) -- needed to diagnose
in-game why item drops are still rare/absent after the drop-rate and
item-index fixes, without guessing at STB drop-table values blind.

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

docker-compose.yml

@@ -23,7 +23,7 @@ x-app: &app
     WORLD_S2S_PORT: ${WORLD_S2S_PORT:-29210}
     WORLD_CHANNEL_NAME: ${WORLD_CHANNEL_NAME:-Channel 1}
     WORLD_MAX_CONNECTIONS: ${WORLD_MAX_CONNECTIONS:-500}
-    WORLD_WELCOME_MSG: ${WORLD_WELCOME_MSG:-Welcome to ROSE}
+    WORLD_WELCOME_MSG: ${WORLD_WELCOME_MSG:-Welcome to ROSS}
     WORLD_SAVE_TIME: ${WORLD_SAVE_TIME:-3600}
     SHARED_LOGIN_PASS: ${SHARED_LOGIN_PASS:-789456}
     SHARED_CHAR_PASS: ${SHARED_CHAR_PASS:-456123}