feat: roadrunner devcontainer

[simonostendorf]

Closes #129

[Copilot]

Pull Request Overview

This PR switches the Laravel Octane server from FrankenPHP to RoadRunner as part of implementing roadrunner devcontainer support. The changes update configuration files to use RoadRunner instead of FrankenPHP as the default Octane server.

• Updates default Octane server configuration from FrankenPHP to RoadRunner
• Comments out FrankenPHP-specific Docker configuration settings

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
docker-compose.sail.yaml	Comments out FrankenPHP-specific supervisor and XDG environment variables
.env.example	Changes default OCTANE_SERVER from frankenphp to roadrunner

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