docs(go2): add getting started guide

[spomichter]

Adds a production-ready getting started guide for the Unitree Go2 at docs/platforms/quadruped/go2/index.md.

Covers: install, replay (no hardware), real robot, module overview, simulation, agentic control, available blueprints, and deep dive links to existing docs.

[greptile-apps]

Greptile Summary

Added a comprehensive production-ready getting started guide for the Unitree Go2 robot platform. The documentation covers installation, replay mode for trying without hardware, real robot operation, simulation, agentic control, and lists all available blueprints with deep dive links to existing documentation.

• Clear installation instructions with platform-specific references
• Progressive complexity: replay → real hardware → simulation → agentic control
• Helpful module overview table explaining what each component does
• All referenced documentation paths and blueprints verified to exist
• Command examples are practical and ready to use

Confidence Score: 5/5

• This PR is safe to merge with no risk - it only adds documentation
• Documentation-only change that improves user onboarding. All referenced files, blueprints, and commands have been verified to exist in the codebase. No code changes that could introduce bugs or security issues
• No files require special attention

Important Files Changed

Filename	Overview
docs/platforms/quadruped/go2/index.md	Well-structured getting started guide with clear installation steps, usage examples, and comprehensive module/blueprint documentation

_{Last reviewed commit: 47b6492}

[greptile-apps]

_{1 file reviewed, no comments}

_{Edit Code Review Agent Settings | Greptile}

[leshy]

needs to go out of the bash block and be a proper link