docs: comprehensive README overhaul with modern structure and detailed content

MAJOR README UPDATE:

New Structure:
- 🎯 Clear problem/solution statement
- ✨ Feature highlights with visual tables
- 🚀 Streamlined quick start guide
- 📖 Comprehensive documentation links
- 🎨 Real-world examples and use cases
- 🛠️ Complete MCP tools reference (17 tools)
- 🏗️ Multi-instance architecture diagram
- 🔒 Security and best practices section
- 🐛 Collapsible troubleshooting guides
- 📊 What's New section with version highlights
- 🗺️ Roadmap (completed, in progress, planned)
- 🤝 Contributing guidelines
- 🙏 Acknowledgments section

Content Improvements:
- Added SEO-optimized hero section
- Included all 17 tools with descriptions
- Added multi-instance architecture visualization
- Expanded security best practices
- Added troubleshooting accordion/dropdowns
- Included version history highlights
- Added contributing and development setup
- Improved visual hierarchy with emojis
- Added quick navigation links
- Better examples and use cases

From 1048 lines → 579 lines of focused, high-quality content

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: salacoste