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/knowledge/source/csv_knowledge_source.py

@@ -1,6 +1,5 @@
 import csv
 from pathlib import Path
-from typing import Dict, List
 
 from crewai.knowledge.source.base_file_knowledge_source import BaseFileKnowledgeSource
 
@@ -8,7 +7,7 @@ from crewai.knowledge.source.base_file_knowledge_source import BaseFileKnowledge
 class CSVKnowledgeSource(BaseFileKnowledgeSource):
     """A knowledge source that stores and queries CSV file content using embeddings."""
 
-    def load_content(self) -> Dict[Path, str]:
+    def load_content(self) -> dict[Path, str]:
         """Load and preprocess CSV file content."""
         content_dict = {}
         for file_path in self.safe_file_paths:
@@ -32,7 +31,7 @@ class CSVKnowledgeSource(BaseFileKnowledgeSource):
         self.chunks.extend(new_chunks)
         self._save_documents()
 
-    def _chunk_text(self, text: str) -> List[str]:
+    def _chunk_text(self, text: str) -> list[str]:
         """Utility method to split text into chunks."""
         return [
             text[i : i + self.chunk_size]