⚡ Bolt: [performance improvement: Optimize DataFrame iterations]

[alinelena]

💡 What: Replaced the slow iterrows() with to_dict('records') (when keys are dynamic) and itertuples(index=False, name=None) (when accessing by position) in calc_elasticity.py, gscdb138.py, calc_solvMPCONF196.py, and calc_MPCONF196.py.
🎯 Why: iterrows() is a well-known bottleneck in Pandas because it converts each row to a Series, incurring significant overhead. itertuples returns a standard tuple, and to_dict('records') returns standard dictionaries, both bypassing Series creation and providing faster iterations in hot loops.
📊 Impact: Substantial speedup for DataFrame iterations in calculation scripts, reducing overhead when handling large benchmark datasets.
🔬 Measurement: Run the tests in tests/ and script-specific pytest tests to ensure behavior remains identical while iterations complete faster.

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PR created automatically by Jules for task 9893097340615874708 started by @alinelena

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