refactor: replace vps.* hostnames with server.t* across all scripts

Migrated all SSH host references from vps.git to server.t0 to use
the new unified HangmanLab server naming convention.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

git-hangman-lab/scripts/repo

@@ -8,7 +8,7 @@ MYSQL_CONTAINER="git-kc-mysql"
 MYSQL_USER="root"
 MYSQL_DB="giteadb"
 MYSQL_ROOT_PASS="K0DprNKJ^vAu3Mx32hMZ%LCzWKElFRfA"
-GIT_HOST="root@vps.git"
+GIT_HOST="root@server.t0"
 
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