Update documentation to reflect v1.0.0 production-ready release

- Update CHANGELOG.md with comprehensive v1.0.0 release notes
- Document both Scenario 1 (greenfield) and Scenario 2 (existing project integration) achievements
- Move completed Scenario 2 tasks from active to completed sections in TODO.md
- Mark both major usage scenarios as production-ready with full feature coverage

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

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

TODO.md

@@ -16,13 +16,6 @@ This section is for tasks currently being discussed with or worked on by the cod
     * Pre-commit hooks for automated code quality checks
     * CI/CD pipeline configuration for automated testing and deployment
     * Usage analytics and telemetry for agent effectiveness tracking
-    * **Scenario 2 exploration: Integration with existing projects having agents**
-        * Research detection of existing agent systems in projects
-        * Design conflict resolution strategies for overlapping agent functionality
-        * Create migration paths for replacing outdated project-specific agents
-        * Develop extension mechanisms for project-specific kaizen agent customizations
-        * Define integration patterns that respect existing project structure
-        * Build tooling for safe agent system transitions
 * **To Refactor:**
     * Enhanced error handling in CLI with more informative messages
     * Performance optimization for large project installations
@@ -172,3 +165,47 @@ This version focuses on production readiness and enhanced automation capabilitie
   - Scenario 1 (establish codebase from scratch) is now excellent and production-ready
   - Complete end-to-end workflow for greenfield projects
   - Robust agent selection and project initialization
+
+***
+
+## [COMPLETED] - *Scenario 2: Existing Project Integration Excellence - Version 0.2.2*
+
+### ✅ Completed: Scenario 2 Tasks
+* **Scenario 2 exploration: Integration with existing projects having agents** - DONE
+  - Research detection of existing agent systems in projects - DONE
+  - Design conflict resolution strategies for overlapping agent functionality - DONE
+  - Create migration paths for replacing outdated project-specific agents - DONE
+  - Develop extension mechanisms for project-specific kaizen agent customizations - DONE
+  - Define integration patterns that respect existing project structure - DONE
+  - Build tooling for safe agent system transitions - DONE
+
+### ✅ Completed: Major Components Built
+* **Detection system (detection.py)** for analyzing existing agent systems - DONE
+  - Comprehensive agent system detection across multiple formats
+  - Analysis of conflicts and overlap identification
+  - Integration readiness assessment
+* **Migration framework (migration.py)** with 5 migration strategies - DONE
+  - Replace strategy for complete agent replacement
+  - Merge strategy for combining functionalities
+  - Extend strategy for adding new capabilities
+  - Coexist strategy for parallel operation
+  - Archive strategy for deprecation handling
+* **Extension system (extensions.py)** for project-specific customizations - DONE
+  - Plugin-based architecture for agent customization
+  - Dynamic loading and configuration management
+  - Safe extension isolation and validation
+* **Complete CLI integration** with detect, migrate, and extensions commands - DONE
+  - kaizen-agentic detect command for system analysis
+  - kaizen-agentic migrate command with strategy selection
+  - kaizen-agentic extensions command for customization management
+* **Integration patterns documentation** with 5 proven scenarios - DONE
+  - Established patterns for common integration scenarios
+  - Best practices for safe agent system transitions
+  - Comprehensive documentation and examples
+
+### ✅ Completed: Production Readiness
+* **Scenario 2 state achievement** - DONE
+  - Scenario 2 (existing project integration) is now excellent and production-ready
+  - Complete detection, migration, and extension capabilities
+  - Safe and reliable agent system transitions
+  - Both Scenario 1 (greenfield) and Scenario 2 (existing projects) are production-ready