Python: Replace wildcard imports with explicit imports

[eavanvalkenburg]

Fixes #3605

Summary

Replaced all wildcard imports (from ... import *) with explicit symbol imports across the Python codebase.

Changes

• Core package (agent_framework/__init__.py): Replaced 10 wildcard imports with explicit imports for ~100 symbols
• OpenAI subpackage (agent_framework/openai/__init__.py): Replaced 6 wildcard imports with explicit imports
• Lab namespace packages: Replaced 3 wildcard imports with explicit imports and added __all__ declarations for re-exports
• CODING_STANDARD.md: Added explicit guidance prohibiting wildcard imports with rationale

Impact

• API: No breaking changes - all previously exported symbols remain available
• Clarity: Makes public API explicit and improves code navigation
• Performance: Eliminates unnecessary symbol resolution during imports
• Tooling: Better IDE autocomplete, go-to-definition, and type checking

Testing

• Ran core test suite: 812 passed, 18 skipped
• Verified ruff checks pass on all modified files
• Confirmed wildcard import count: 19 → 0

Wildcard Count

• Before: 19 wildcard imports
• After: 0 wildcard imports

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
TOTAL	20472	3247	84%

report-only-changed-files is enabled. No files were changed during this commit :)

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3918	225 💤	0 ❌	0 🔥	1m 7s ⏱️

[Copilot]

Pull request overview

This pull request successfully eliminates all wildcard imports (from ... import *) across the Python codebase and replaces them with explicit symbol imports. The changes affect the core agent_framework package, the openai subpackage, and three lab namespace packages (tau2, lightning, gaia).

Changes:

• Replaced 10 wildcard imports in the core package with ~100 explicit imports using the import X as X pattern for re-exporting
• Replaced 6 wildcard imports in the OpenAI subpackage with explicit imports
• Replaced 3 wildcard imports in lab namespace packages and added __all__ declarations
• Updated CODING_STANDARD.md to prohibit wildcard imports and document the rationale

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
python/packages/core/agent_framework/init.py	Replaced 10 wildcard imports with 387 lines of explicit imports using import X as X pattern
python/packages/core/agent_framework/openai/init.py	Replaced 6 wildcard imports with explicit imports for 13 symbols
python/packages/lab/namespace/agent_framework/lab/tau2/init.py	Replaced wildcard import with explicit imports for 6 symbols and added __all__
python/packages/lab/namespace/agent_framework/lab/lightning/init.py	Replaced wildcard import with explicit import for 1 symbol and added __all__
python/packages/lab/namespace/agent_framework/lab/gaia/init.py	Replaced wildcard import with explicit imports for 10 symbols and added __all__
python/CODING_STANDARD.md	Added prohibition of wildcard imports with rationale and examples