feat: add review_pending_changes tool and enforce absolute path security

- Add new review_pending_changes tool for comprehensive pre-commit reviews
- Implement filesystem sandboxing with MCP_PROJECT_ROOT
- Enforce absolute paths for all file/directory operations
- Add comprehensive git utilities for repository management
- Update all tools to use centralized path validation
- Add extensive test coverage for new features and security model
- Update documentation with new tool and path requirements
- Remove obsolete demo and guide files

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

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

tests/test_server.py

@@ -25,11 +25,12 @@ class TestServerTools:
         assert "debug_issue" in tool_names
         assert "analyze" in tool_names
         assert "chat" in tool_names
+        assert "review_pending_changes" in tool_names
         assert "list_models" in tool_names
         assert "get_version" in tool_names
 
-        # Should have exactly 7 tools
-        assert len(tools) == 7
+        # Should have exactly 8 tools
+        assert len(tools) == 8
 
         # Check descriptions are verbose
         for tool in tools: