changelog.md for @fin.cx/calculation

[1.0.0] - 2025-07-29 
 Added 
 
 Initial release of @fin.cx/calculation 
 Calculator class with high-precision decimal arithmetic 
 Financial class with time value of money calculations (PV, FV, NPV, IRR, XIRR) 
 Interest class with simple, compound, and continuous interest calculations 
 Amortization class with loan schedules and payment analysis 
 Currency class with conversion, formatting, and monetary operations 
 Comprehensive test suite 
 Full TypeScript support 
 CI/CD workflows for automated testing and publishing