feat: Add tree-sitter query-based core library with method/function distinction

- Create `code_extractor/` core library package with rich data models
- Implement tree-sitter query engine solving method vs function classification
- Add comprehensive pytest test suite with 100% pass rate
- Build new MCP server using core library with enhanced functionality

Key improvements:
- Methods now correctly classified as "method" not "function"
- Rich context extraction: parameters, return types, async detection, docstrings
- Hierarchical parent relationships (methods show parent class)
- Query-based extraction replacing manual tree traversal
- Proper symbol boundaries using definition nodes
- Enhanced testing infrastructure with fixtures

Technical details:
- CodeSymbol/Parameter dataclasses for structured representation
- Python tree-sitter queries handling async, decorated, and nested methods
- Two-pass capture processing for accurate symbol matching
- Language detection and parser management system
- Backward-compatible MCP interface with enhanced output

🤖 Generated with Claude Code

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

Author: ctoth

code_extractor/__init__.py

@@ -0,0 +1,11 @@
+"""
+MCP Server Code Extractor - Core Library
+
+A powerful code extraction library using tree-sitter for precise syntax analysis.
+"""
+
+from .models import CodeSymbol, Parameter, SymbolKind
+from .extractor import CodeExtractor, create_extractor
+
+__version__ = "0.2.0"
+__all__ = ["CodeSymbol", "Parameter", "SymbolKind", "CodeExtractor", "create_extractor"]