This pull request refactors and improves the storage and error handling infrastructure for the Microsoft Agents activity and hosting core libraries. The main changes involve modularizing utility functions, introducing new storage namespace abstractions, and replacing custom storage client logic with standardized wrappers for managing state. These updates simplify code maintenance, enhance clarity, and make state management more robust and consistent.

Error handling and utility improvements:

• Added _raise_if_none and _raise_if_falsey helper functions for input validation, and moved load_configuration_from_env to a new _utils module for better organization. [1] [2] [3] [4]

Storage abstraction and namespace improvements:

• Introduced _Namespaces and storage wrapper classes (_ItemNamespace, _StorageNamespace, _ItemStorage) to standardize namespacing and item management in storage operations. These are now exported in the storage package for use across the codebase. [1] [2]
• Updated the OAuth authorization logic to use _ItemNamespace for sign-in state management, replacing custom key generation and CRUD methods with standardized wrapper calls. [1] [2] [3] [4] [5] [6] [7] [8]

Removal of legacy code and simplification:

• Removed the _FlowStorageClient class and its usage, replacing it with _ItemNamespace and standardized storage wrappers for OAuth flow state management. [1] [2] [3] [4] [5] [6]

Internal API consistency:

• Refactored handler initialization to use _StorageNamespace for isolating storage per handler, improving separation of concerns and consistency.

Documentation and code clarity:

• Updated copyright and license headers, and improved docstrings for new utility functions and storage abstractions. (libraries/microsoft-agents-activity/microsoft_agents/activity/_utils/init.pyR1-R14, F70870536R1)