Refactor: Add initialization helper to CoreUtilsMixin

[pyob-bot]

Summary of Changes

• Introduced a new _ensure_initialized method to CoreUtilsMixin.
• This method provides a centralized way to initialize essential attributes (target_dir, memory_path, key_cooldowns, and _workspace_cache) if they have not been previously set.

Technical Impact

• Improves robustness by ensuring required state variables are present before use, preventing potential AttributeError exceptions.
• Simplifies object initialization logic across classes inheriting from CoreUtilsMixin.