[PHASE-9] Update implementation plan

docs/IMPLEMENTATION.md

@@ -109,12 +109,25 @@
 - [X] Implement configuration management using cleanenv library
 - [X] Read configuration from file with environment variable support
 
-## Phase 9: Documentation
+## Phase 9: Documentation & Final Polish
 - [X] Create comprehensive README.md with project overview and quick start
 - [X] Document package structure and responsibilities
 - [X] Document architecture choices and design decisions
 - [X] Update production readiness assessment
+- [X] Fix graceful shutdown implementation with proper context handling
+- [X] Add Go runtime metrics to Prometheus endpoint
+- [X] Correct architectural documentation inaccuracies
 
+## Development Complete
+
+All planned phases have been implemented. The Hash of Wisdom server is now:
+- ✅ **Functionally Complete**: Full proof-of-work challenge-response system
+- ✅ **Production Instrumented**: Metrics, profiling, logging, graceful shutdown
+- ✅ **Containerized**: Docker-ready with security best practices
+- ✅ **Well Documented**: Comprehensive technical documentation
+- ✅ **Battle Tested**: Integration tests for security and performance
+
+For production deployment, see [Production Readiness Guide](PRODUCTION_READINESS.md) for remaining requirements.
 
 ## Directory Structure
 ```