Fix comment bot panic when !check is used with hostname-only address

[Copilot]

ac-server-monitor requires host:port format for -check, but the comment bot was passing only the hostname (e.g., play.coldeve.ac), causing a panic and exit code 2.

Changes

• Checkout repository first — adds actions/checkout@v4 before the extract step so Servers.xml is available
• Auto-resolve port from Servers.xml — when the provided address has no :, Python parses Servers.xml to look up the matching server_port; falls back to the bare hostname if not found
• Pass-through for host:port input — if the comment already includes a port, it's used as-is

INPUT=$(echo "${{ github.event.comment.body }}" | awk '{print $2}')
if echo "$INPUT" | grep -q ':'; then
  echo "ADDRESS=$INPUT" >> $GITHUB_OUTPUT
else
  PORT=$(python3 -c "
import xml.etree.ElementTree as ET, sys
...
if host.text.strip() == sys.argv[1]:
    print(port.text.strip())
" "$INPUT")
  echo "ADDRESS=$INPUT:$PORT" >> $GITHUB_OUTPUT
fi

[amoeba]

(Just testing copilot on this since I haven't done it much)

[amoeba]

!check the-tower.ddns.net

[github-actions]

⏳ Checking if I can connect and log in to the-tower.ddns.net. Give me a minute...

[github-actions]

✅ the-tower.ddns.net was up and I was able to log in!