docs: enhance deployment guide with prerequisites and common pitfalls

[IEvangelist]

Adjusted a few minor bits based on @DamianEdwards video:

• Remove highlighting of package reference directives, as it was confusing
• Added clarifying context where applicable
• Reorganized the flow a bit

[Copilot]

Pull request overview

This PR enhances the deployment guide documentation by reorganizing content for better readability and adding clearer guidance on prerequisites and common pitfalls when deploying Aspire apps.

Changes:

• Added introductory text to the Prerequisites section
• Moved the "Common pitfall" note after the deployment examples for better context
• Moved the aspire deploy command and explanation into tab-specific sections

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