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/gitea

@@ -1,7 +1,7 @@
 #!/bin/bash
 set -euo pipefail
 
-REMOTE_HOST="vps.git"
+REMOTE_HOST="server.t0"
 REMOTE_USER="root"
 CONTAINER_NAME="git-kc-gitea"