Move documentation to docs/ directory and improve terminology

- Move ARCHITECTURE.md and CLAUDE.md to docs/ directory
- Replace "real-time" terminology with accurate "low-latency" and "high-performance"
- Update README to reflect correct performance characteristics
- Add comprehensive ICAO country database with SQLite backend
- Fix display options positioning and functionality
- Add map scale controls and improved range ring visibility
- Enhance aircraft marker orientation and trail management

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

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

docs/CLAUDE.md

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+# SkyView Project Guidelines
+
+## Documentation Requirements
+- We should always have an up to date document describing our architecture and features
+- Include links to any external resources we've used  
+- We should also always have an up to date README describing the project
+- Shell scripts should be validated with shellcheck
+- Always make sure the code is well documented with explanations for why and how a particular solution is selected
+
+## Development Principles
+- An overarching principle with all code is KISS, Keep It Simple Stupid
+- We do not want to create code that is more complicated than necessary
+- When changing code, always make sure to update any relevant tests
+- Use proper error handling - aviation applications need reliability
+
+## SkyView-Specific Guidelines
+
+### Architecture & Design
+- Multi-source ADS-B data fusion is the core feature - prioritize signal strength-based conflict resolution
+- Embedded resources (SQLite ICAO database, static assets) over external dependencies
+- Low-latency performance is critical - optimize for fast WebSocket updates
+- Support concurrent aircraft tracking (100+ aircraft should work smoothly)
+
+### Code Organization
+- Keep Go packages focused: beast parsing, modes decoding, merger, server, clients
+- Frontend should be modular: separate managers for aircraft, map, UI, websockets
+- Database operations should be fast (use indexes, avoid N+1 queries)
+
+### Performance Considerations
+- Beast binary parsing must handle high message rates (1000+ msg/sec per source)
+- WebSocket broadcasting should not block on slow clients
+- Memory usage should be bounded (configurable history limits)
+- CPU usage should remain low during normal operation
+
+### Documentation Maintenance
+- Always update docs/ARCHITECTURE.md when changing system design
+- README.md should stay current with features and usage
+- External resources (ICAO docs, ADS-B standards) should be linked in documentation
+- Country database updates should be straightforward (replace SQLite file)