Fix/z image controlnet logging (supersedes #9289)

[lstein]

Summary

Reposting PR #9289 because it needed a merge and the author did not authorize write permissions by maintainer.

The original PR summary follows:

• replace unconditional [DEBUG] / [WARNING] terminal output in z_image_controlnet_extension.py with module logger calls
• add a regression test that checks initialization diagnostics do not write to stdout and still emit logging calls

Why

These diagnostics come from backend/library code and currently print directly to stdout, which can pollute terminal output and make log handling inconsistent for downstream callers.

Validation

• added a regression test for constructor diagnostics behavior
• verified the updated source and test files with py_compile
• ran a source-level regression check to confirm the debug output is no longer implemented with direct print(...) calls

Note

The full pytest dependency set for this repository was not available in the current local environment, so I validated this change with targeted static checks plus compile-time verification.