fix: update DayZ workshop mods via SteamCMD

[saulane]

Closes #215

Summary:

• Detect DayZ @mod folders by parsing meta.cpp and reading publishedid values, including values with trailing semicolons.
• Download those Workshop IDs with SteamCMD using the DayZ Workshop app ID 221100.
• In AUTOMATIC mode, replace the local mod directory from the downloaded Workshop content and copy .bikey files into the server keys directory.
• Allow Steam app IDs to skip Minecraft version discovery so DayZ updates can run without Minecraft metadata.

Tests:

• javac --release 9 -d /private/tmp/autoplug-compile src/main/java/com/osiris/autoplug/client/tasks/updater/mods/DayZWorkshopModUpdater.java
• javac --release 9 -cp /private/tmp/autoplug-compile -d /private/tmp/autoplug-compile /private/tmp/TestDayZWorkshopModUpdater.java
• java -cp /private/tmp/autoplug-compile TestDayZWorkshopModUpdater
• git diff --check

Note: mvn test was not available because Maven is not installed in this environment.