Add comprehensive tests for ast-grep and tree-sitter relationship extraction

- Introduced test suite for AstGrepPythonProcessor covering pattern definitions, parsing, and relationship extraction.
- Added comparison tests between tree-sitter and ast-grep for consistency in relationship extraction.
- Implemented tests for ast-grep binding module to verify functionality and availability.
- Ensured tests cover various scenarios including inheritance, function calls, and imports.

codex-lens/pyproject.toml

@@ -22,6 +22,9 @@ dependencies = [
     "tree-sitter-typescript>=0.23",
     "pathspec>=0.11",
     "watchdog>=3.0",
+    # ast-grep for pattern-based AST matching (PyO3 bindings)
+    # Note: May have compatibility issues with Python 3.13
+    "ast-grep-py>=0.3.0; python_version < '3.13'",
 ]
 
 [project.optional-dependencies]