Improve pytest configuration and testing structure

[guan404ming]

Purpose of PR

Update testing setup to be more closely aligned with pytest conventions and Poetry dependency management.

Linked Issues

part of #572

Changes Made

• Bug fix
• New feature
• Documentation update

Important ToDos

Please mark each with an "x"

A GitHub issue exists (if not, please create one) [https://github.com/apache/mahout/issues]

• Title of PR is "Issue #XXXX: Brief Description of Changes" where XXXX is the GitHub issue number.
• Created unit tests where appropriate (enhanced existing tests with pytest conventions)
• Added correct licenses on newly added files
• Assigned GitHub issue to self
• Added documentation in ScalaDocs/JavaDocs and to the website (updated testing README)
• Successfully built and ran all unit tests, verified that all tests pass locally

If all of these items are not yet complete, but you still feel it is appropriate to open a PR, please open it as a Draft PR
instead.
Once all requirements are met, you can mark it as ready for review.

Breaking Changes

Does this PR introduce a breaking change?

• Yes
• No

Testing & Verification

Describe how you tested the changes.

• Unit tests added (enhanced existing tests with pytest features)
• Manually tested (verified all test commands work correctly)

Testing performed:

• All tests pass with poetry run pytest
• Parametrized tests work correctly for multiple quantum states
• Test collection and execution work with new structure

Checklist

• The title follows the format "MAHOUT-XXXX Brief Description"
• GitHub issue is created
• Code follows ASF guidelines

[guan404ming]

I think this one could improve the test infra as well. I would appreciate it if you could take a look, thanks!
cc @andrewmusselman

[rawkintrevo]

@guan404ming can you resolve conflicts?

[guan404ming]

Sure, I've resolved it. Also, CI failed would be fixed in #578.

[rawkintrevo]

Thanks @guan404ming - could you make issues to expand to cirq and bracket?