Validate side_damage_ratio.csv shape and constraints #14
Description
Problem
- Malformed ratios can silently skew cladding allocation.
Proposed solution
- Add shape/value checks and descriptive errors.
Permalink to context in #8: https://github.com/OpenPBEE/Functional-Recovery-Python/pull/8/changes#diff-09ddbe9b47cd801ac2851f14da73cf459f44c2cd8c6d3f2a557541ff2a6bc4b2R609