Python: improved loading

[eavanvalkenburg]

Motivation and Context

Made some improvements to the loading setup.
In the main package, all modules are just loaded, there is very little gain in lazy loading and it leads to extra complexity.
Now added a __all__ to each file, that is the only place you need to specify what is part of the public API for that file.
In the main init all submodules are loaded with the *, which type checkers understand as loading everything from all.

In Azure, and that can be the blueprint for all files, simplified the setup as well:

• add public components to _IMPORTS variable and to init.pyi
• currently there is no way to do a multilevel import in a subpackage, so keep all packages simple with single level imports, which is desired anyway.

Description

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[Copilot]

Pull Request Overview

This PR improves the Python package loading structure by standardizing the use of __all__ declarations and simplifying import patterns. The changes move away from lazy loading in favor of explicit star imports that leverage __all__ for better type checker compatibility.

Key changes:

• Adds __all__ declarations to all module files to define public APIs
• Replaces lazy loading with star imports in __init__.py files
• Simplifies the Azure package loading mechanism

Reviewed Changes

Copilot reviewed 16 out of 17 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
agent_framework/init.py	Replaced lazy loading with star imports from submodules
agent_framework/init.pyi	Removed type stub file (now handled by all declarations)
agent_framework/azure/init.py	Simplified loading mechanism and improved error handling
agent_framework/azure/init.pyi	Added type stub for Azure package imports
Multiple module files	Added all declarations to define public APIs
.vscode/settings.json	Updated code actions to use Ruff-specific settings