chore: Cleanup docs

[tymondesigns]

This pull request makes broad documentation cleanups and simplifications across the JSON Schema docs. The main focus is on removing repetitive "Next Steps" card groups at the end of most pages, eliminating redundant resource links, and streamlining installation and quickstart instructions. Additionally, some minor formatting improvements and clarifications are made to tips and code blocks.

The most important changes include:

Documentation Structure Simplification:

• Removed nearly all "Next Steps" card groups from advanced and schema type documentation pages to reduce repetition and improve readability. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]

• Removed the "Validation" group and its pages from the sidebar navigation in docs.json, further simplifying navigation.

Content and Formatting Improvements:

• Removed the "Additional Resources" section from the MCP server documentation.
• Streamlined the installation guide by removing redundant verification steps and the "Quick Start Guide" card. [1] [2]
• Updated quickstart and feature overview pages to remove redundant "Next Steps" and resource cards, and replaced <Check> blocks with <Tip> for improved clarity. [1] [2] [3] [4] [5] [6]

Content Reduction:

• Removed the detailed "Loading from Files" and "Best Practices" sections from the "From JSON" code generation documentation, focusing the page on common use cases and reducing length.

Navigation and Linking Adjustments:

• Removed or adjusted links to validation and version feature guides in the introduction and other overview cards. [1] [2]

These changes collectively make the documentation less repetitive, easier to navigate, and more focused on core concepts and examples.