Show a GitHub star message after `install:demo` completes successfully

Summary

Show a short console message after install:demo completes successfully, inviting the user to star the Quantum repository on GitHub.

Why

The project creation flow already runs:

• php qt install:demo --yes

through post-create-project-cmd.

That makes the demo install command one of the first guided experiences users see after creating a new Quantum project.

At the moment, install:demo ends with:

• Demo project created successfully

This is a reasonable place to show a small follow-up message asking users to support the framework by starring the repository on GitHub.

Goal

Add a concise post-success message to the demo installation command that appears after the demo has been created successfully and includes the repository URL.

Proposed Direction

After the existing success message in install:demo, show a short follow-up line such as:

• Would you like to show some love by starring Quantum on GitHub? https://github.com/softberg/quantum-php-core

Or similar wording, as long as the message remains lightweight and includes the direct repository link.

Acceptance Criteria

• after install:demo completes successfully, a star-message is shown in the console
• the message only appears on successful completion
• the message includes the direct GitHub repository URL
• the message wording is concise and does not interrupt the installation flow

Notes

Relevant code:

• shared/Commands/DemoCommand.php
• composer.json post-create-project script

Start in shared/Commands/DemoCommand.php and locate the existing successful completion message for install:demo. Add a concise follow-up containing https://github.com/softberg/quantum-php-core, ensuring it is reached only after successful completion. Run php qt install:demo --yes and confirm the message appears after the success output without interrupting the flow.