feat: macOS support via Docker Desktop mode + fix Docker Desktop localhost seeding

[drakeshnag-rjo]

Changes

• macOS compose file mirroring the Windows Docker Desktop variant: POSIX socket path, secrets from .env, healthcheck start_period for slow first-boot postgres init.
• Native macOS installer (install.sh cannot run on Macs: no os-release, no systemd, read-only root, no root SSH). Verifies Docker 24+ and Compose v2, prepares data dirs and .env, starts the stack, waits for health.
• IS_DOCKER_DESKTOP added as platform-neutral alias for the old Windows-named variable (which still works and takes precedence).
• Seeder fix: the generic self-hosted block created server 0 with the wrong ip before the Docker Desktop block ran, so server and key never matched and onboarding said unreachable. Added the flag guard already used earlier in the seeder.

Issues

• Fixes Docker Desktop mode seeds localhost server with wrong IP/key (host.docker.internal instead of coolify-testing-host) #10931
• Fixes macOS support for self-hosted Coolify via Docker Desktop mode (docker-compose.mac.yml + install-mac.sh) #10932
• Supersedes feat: macOS support via Docker Desktop mode + fix Docker Desktop localhost seeding #10933 (bot-closed; flagged items fixed)

Category

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

Preview

Onboarding reaches Setup Complete, localhost server validated; deployment shows Finished/Running. Screenshots on request.

AI Assistance

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

If AI was used:

• Tools used: Claude Code
• How extensively: drafted with AI under my direction; all changes exercised against a live install as described below.

Testing

End-to-end on macOS 12.7.6 (Intel), Colima 0.8.1 / Engine 27.4.0: installer run from a checkout, five containers healthy, root user registered, onboarding validated the localhost server, proxy and Sentinel healthy after the seeder fix (both failed before it), deployed nginx alpine with a port mapping, HTTP 200 from the host. Pest suite left to CI; only PHP changes are the seeder guard and constants alias.

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.