docs: update clusters, add multipass, juju, and vantage agent options.

[wardbryan3]

update platform/clusters section to reflect the new "setup" wizard/ or modal

update sidebar-main.js to include new pages.

clean up relevant sections.

Pull Request Template for Vantage Documentation

Description

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📝 Documentation update (improvements or corrections to documentation content)
• 🎨 Style/formatting change (non-functional changes)
• ♻️ Code refactoring (non-functional changes)
• ⚡ Performance improvement
• 🔧 Configuration change

Documentation Section

• Platform Overview
• Platform Documentation
• API Documentation
• CLI Documentation
• SDK Documentation
• Getting Started
• Site Infrastructure/Configuration

Changes Made

Added

Changed

Removed

Fixed

Testing Checklist

• Local development server runs without errors (just serve)
• Production build completes successfully (just build)
• All internal links are functional
• New content follows markdown/MDX standards
• Content is responsive on mobile devices
• Search functionality works for new content (if applicable)
• No broken links or missing images
• Code examples have been tested (if applicable)

Content Quality Checklist

• Content follows the established writing style and tone
• Technical accuracy has been verified
• Examples are complete and functional
• Appropriate headings and structure used
• Links use relative paths where possible
• Images have descriptive alt text
• Content is accessible and inclusive

Screenshots (if applicable)

Related Issues

Additional Notes

Reviewer Guidelines

• Content accuracy and completeness
• Technical implementation correctness
• Consistency with existing documentation
• Proper formatting and structure
• Mobile responsiveness (if UI changes)
• Build process verification

[jamesbeedy]

+1