Update landing page with clean grayscale-cli styling

- Remove colorful emojis and badges for professional CLI appearance
- Convert all badges to grayscale color scheme
- Streamline project description to be more concise and focused
- Replace complex mermaid diagram with simple feature list
- Consolidate installation instructions into single clear section
- Update AI and MCP sections with cleaner formatting
- Remove redundant sections and duplicate information
- Clean up documentation links and navigation
- Ensure all information is current and relevant
- Create consistent grayscale styling throughout
- Focus on functionality over visual decoration
- Maintain professional CLI tool aesthetic

Co-authored-by: 0xrinegade <[email protected]>

Author: Copilot