chore(v5.2.0): Update CHANGELOG and remove deprecated test files

- Added Skills System Enhancements section to CHANGELOG
- Documented new skills: codeagent, product-requirements, prototype-prompt-generator
- Removed deprecated test files (tests/test_*.py)
- Updated release date to 2025-12-13

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Co-Authored-By: swe-agent-bot <agent@swe-agent.ai>

CHANGELOG.md

@@ -1,9 +1,14 @@
 # Changelog
 
-## 5.2.0 - 2025-12-12
+## 5.2.0 - 2025-12-13
 
 ### 🚀 Core Features
 
+#### Skills System Enhancements
+- **New Skills**: Added `codeagent`, `product-requirements`, `prototype-prompt-generator` to `skill-rules.json`
+- **Auto-Activation**: Skills automatically trigger based on keyword/pattern matching via hooks
+- **Backward Compatibility**: Retained `skills/codex/SKILL.md` for existing workflows
+
 #### Multi-Backend Support (codeagent-wrapper)
 - **Renamed**: `codex-wrapper` → `codeagent-wrapper` with pluggable backend architecture
 - **Three Backends**: Codex (default), Claude, Gemini via `--backend` flag
@@ -32,6 +37,7 @@
 - **Modular Installation**: `python3 install.py --module dev`
 - **Verbose Logging**: `--verbose/-v` enables terminal real-time output
 - **Streaming Output**: `op_run_command` streams bash script execution
+- **Configuration Cleanup**: Removed deprecated `gh` module from `config.json`
 
 ### 📚 Documentation