feat: add Project Zomboid service template

[NosytLabs]

Changes

• Adds a Project Zomboid dedicated server one-click service template.
• Uses Docker Hub image m4lagon/project-zomboid-server:latest, documented from its Docker Hub page and linked source repo.
• Persists saves, configs, logs, player data, and Steam Workshop downloads in named volumes.
• Exposes 16261/udp, 16262/udp, and optional RCON on 27015/tcp.
• Adds Coolify-generated admin and RCON passwords plus common server, preset, mod, and timezone variables.
• Marks the service amd_only because the public image manifest currently exposes Linux amd64.

Issues

• Fixes Add Project Zomboid one-click service template #9919

Category

• Bug fix
• Improvement
• New feature
• Adding new one click service
• Fixing or updating existing one click service

Preview

Smoke-tested with Docker Compose locally. The server reached the Project Zomboid startup success logs and listened on the expected ports.

AI Assistance

• AI was NOT used to create this PR
• AI was used (please describe below)

If AI was used:

• Tools used: OpenAI Codex CLI/app, GitHub CLI, Docker CLI.
• How extensively: Used to research the image options, draft the Coolify service template, run validation commands, and prepare the PR. Human review is still requested before merge.

Testing

• Passed: docker compose config validation for the new compose template. The local warnings about missing generated password env vars are expected outside Coolify.
• Passed: public Docker image manifest lookup for m4lagon/project-zomboid-server:latest.
• Passed: pulled and started the service with Docker Compose using generated-style admin/RCON passwords.
• Passed: startup logs reached Project Zomboid server ready state: SERVER STARTED, Steam enabled, listening on 16261 and 16262, LuaNet initialized, and RCON listening on 27015.
• Passed: stopped the smoke-test Compose project and removed its test volumes.

Contributor Agreement

Important

• I have read and understood the contributor guidelines. If I have failed to follow any guideline, I understand that this PR may be closed without review.
• I have searched existing issues and pull requests (including closed ones) to ensure this isn't a duplicate.
• I have tested all the changes thoroughly with a local development instance of Coolify and I am confident that they will work as expected when a maintainer tests them.