Summary

Adds comprehensive documentation for two advanced production logging features:

1. Log Server (server/log_server.h)

• Centralized log collection server for distributed applications
• Multi-threaded worker pool architecture
• Configuration: host, port, max_connections, compression, encryption
• Factory methods: create_basic(), create_default()
• Deployment patterns: single server, multi-region, ELK integration

2. Crash-Safe Logger (safety/crash_safe_logger.h)

• Signal handler-based emergency flush (SIGSEGV, SIGABRT, SIGTERM, SIGINT)
• Async-signal-safe implementation (no allocations in handlers)
• flush_with_timeout() for deadlock prevention
• Auto-flush background thread for data durability
• Atomic log level management

3. Combined Usage

• Local crash safety + network forwarding topology
• Server-side crash protection
• Complete production deployment examples

Changes

• Created: docs/LOG_SERVER_AND_CRASH_SAFETY.md (1,673 lines)
  • Architecture diagrams for both features
  • Full API reference with code examples
  • Crash safety mechanism explanation
  • Performance overhead benchmarks (2-10% vs standard logger)
  • Deployment topology examples
  • Best practices and troubleshooting guide

Related Issues

Closes #431

Part of: [EPIC] docs: Address documentation gaps across all ecosystem systems (kcenon/common_system#325)

Test Plan

• Documentation builds without errors
• All code examples compile and follow existing patterns
• Cross-references to related docs verified (CONFIGURATION_STRATEGIES.md, WRITER_GUIDE.md, SECURITY_GUIDE.md)
• API signatures match header files (log_server.h, crash_safe_logger.h)
• Deployment examples validated against current architecture

Documentation Coverage

✅ Log server architecture with component diagram
✅ Log server API fully documented with examples
✅ Server configuration examples (basic, high-volume, secure)
✅ Crash-safe logger mechanism explained
✅ Crash-safe logger API documented with method details
✅ Recovery procedure documented
✅ Performance overhead analysis with benchmarks
✅ Deployment topology examples (3 patterns)
✅ Integration examples (Docker, programmatic control)
✅ Best practices section
✅ Troubleshooting guide

Reviewer Notes

Key sections to review:

1. Architecture Diagrams (lines 25-73): Distributed logging topology
2. Crash Safety Mechanism (lines 645-733): Signal handler flow and async-signal-safe constraints
3. Performance Benchmarks (lines 987-1023): Overhead measurements
4. Combined Topology (lines 1193-1293): Production deployment example
5. Troubleshooting (lines 1409-1580): Common issues and solutions

All examples follow existing code patterns and are production-ready.