[D04] parse_ccx_results.py: Deflection + σₓₓ

[Siddardth7]

Due: March 30 | Day 4 of 14

• Create fea/parse_ccx_results.py
• Print raw baseline.dat content — understand CalculiX output format
• Extract centre node U3 deflection (highest magnitude U3 value)
• Extract σₓₓ (S11) at top and bottom surfaces of critical ply
• Print both to stdout with units and field labels
• Sanity check: deflection should be negative (downward), σₓₓ tensile on bottom ply

✅ Done when: python fea/parse_ccx_results.py fea/baseline.dat prints non-zero, physically reasonable deflection + σₓₓ.