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>

tools/__init__.py

@@ -6,6 +6,7 @@ from .analyze import AnalyzeTool
 from .chat import ChatTool
 from .debug_issue import DebugIssueTool
 from .review_code import ReviewCodeTool
+from .review_pending_changes import ReviewPendingChanges
 from .think_deeper import ThinkDeeperTool
 
 __all__ = [
@@ -14,4 +15,5 @@ __all__ = [
     "DebugIssueTool",
     "AnalyzeTool",
     "ChatTool",
+    "ReviewPendingChanges",
 ]