fix: Replace deprecated typing imports with built-in types

- Replace Dict, List, Set, Tuple with dict, list, set, tuple throughout codebase
- Add missing type annotations to crew_events.py methods
- Add proper type annotations to test_crew_cancellation.py
- Use type: ignore[method-assign] comments for mock assignments
- Maintain backward compatibility while modernizing type hints

This resolves lint and type-checker failures in CI while preserving
the cancellation functionality.

Co-Authored-By: João <joao@crewai.com>

src/crewai/flow/path_utils.py

@@ -7,7 +7,7 @@ traversal attacks and ensure paths remain within allowed boundaries.
 
 import os
 from pathlib import Path
-from typing import List, Union
+from typing import Union
 
 
 def safe_path_join(*parts: str, root: Union[str, Path, None] = None) -> str:
@@ -101,7 +101,7 @@ def validate_path_exists(path: Union[str, Path], file_type: str = "file") -> str
         raise ValueError(f"Invalid path: {str(e)}")
 
 
-def list_files(directory: Union[str, Path], pattern: str = "*") -> List[str]:
+def list_files(directory: Union[str, Path], pattern: str = "*") -> list[str]:
     """
     Safely list files in a directory matching a pattern.
 
@@ -114,7 +114,7 @@ def list_files(directory: Union[str, Path], pattern: str = "*") -> List[str]:
 
     Returns
     -------
-    List[str]
+    list[str]
         List of matching file paths.
 
     Raises