Min Python version >= 3.9 for users & >= 3.10 for developers

[sou-cheng-choi]

Summary

The primary goal is to update the CI/CD workflow to correctly manage and enforce the minimum required Python version for QMCPy users and developers. The developer floor is higher because development dependencies such as current pytest and parsl requires Python 3.10+.

• Issue: 583
• Algorithmic or API impact: None
• Commands run:

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Checklist

• I linked the relevant issue or explained why none was needed.
• I added or updated tests, docs, notebooks, or explained why they were not needed.
• I verified any equations, citations, benchmarks, numerical claims, or external references changed in this PR.
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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.62%. Comparing base (dc3d923) to head (6bf54c0).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #606      +/-   ##
===========================================
- Coverage    88.65%   88.62%   -0.04%     
===========================================
  Files          104      104              
  Lines         8508     8508              
===========================================
- Hits          7543     7540       -3     
- Misses         965      968       +3     

Flag	Coverage Δ
alltests	88.62% <100.00%> (-0.04%)	⬇️

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Files with missing lines	Coverage Δ
...rete_distribution/digital_net_b2/digital_net_b2.py	91.42% <100.00%> (-1.23%)	⬇️

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