[Tech debt] Deprecate statCalculator.js

[fribbels]

Motivation

https://github.com/fribbels/hsr-optimizer/blob/main/src/lib/statCalculator.js

This was a remnant of a previous version of the optimizer before we moved to web workers, currently duplicates logic from https://github.com/fribbels/hsr-optimizer/blob/main/src/lib/optimizer/calculateStats.js

Goal

Remove statCalculator.js and migrate its existing usages. Its currently only used for the character card stats