⚡ Bolt: Replace iterrows with itertuples for faster iteration

[alinelena]

💡 What: Replaced slow .iterrows() calls in Pandas DataFrame iteration with faster alternatives .itertuples() and .to_dict('records').
🎯 Why: iterrows() wraps every row into a Pandas Series object which is notoriously slow and acts as a significant performance bottleneck in the calc_elasticity, calc_solvMPCONF196, calc_MPCONF196, and gscdb138 benchmark parsers.
📊 Impact: Considerably faster loops while parsing inputs and reference energies across several benchmarks with 0 functionality changes.
🔬 Measurement: Verified with ruff check and confirmed behavior mappings remain unchanged. Evaluated itertuples(index=False) vs to_dict("records") to ensure safety around dynamically named indexing.

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PR created automatically by Jules for task 7621705560263874079 started by @alinelena

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