fix: create standalone Docker networks with IPv6 fallback

[gkemqk]

Changes

• Added dockerNetworkCreateCommand() for Coolify-managed network creation.
• Standalone Docker networks now try docker network create --attachable --ipv6 first, then fall back to the current IPv4-only create command when IPv6 is unavailable.
• Reused the helper in proxy setup, server install/validation, Docker Compose app deployment, and service startup network creation paths.
• Left swarm overlay network creation unchanged because overlay IPv6 has separate Docker constraints.

Issues

• Fixes [Bug]: Randomly receiving proxy IP as X-Forwarded-For header using Traefik or Caddy #3436
• Related to fix: add --ipv6 flag to docker network create for proper X-Forwarded-For with IPv6 clients #9570; this alternative adds fallback behavior and covers additional network creation paths.

Category

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

Preview

No UI change. The generated commands are covered by unit tests for standalone IPv6 creation, IPv4 fallback, and swarm behavior.

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, GitHub CLI, Composer/Pest, Laravel Pint.
• How extensively: Codex helped inspect the affected paths, make the code change, run tests, and prepare the PR text.

Testing

• vendor\bin\pest tests\Unit\ProxyHelperTest.php - 28 passed, 34 assertions.
• vendor\bin\pint --test on all changed PHP files - pass.
• git diff --check HEAD~1..HEAD - pass.
• Docker CLI was installed locally, but Docker Desktop's daemon did not become ready in this Windows session, so I could not run a live Docker network demo.

Payment details are intentionally omitted from the public PR body; payout setup should go through Algora's private payment flow.

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.

[github-actions]

This PR did not pass quality checks so it will be closed. If you believe this is a mistake please let us know.