Rewrite item removal logic to fix incorrect change and denomination breakdown

[CodahWasTaken]

Fix: Currency change calculation bug

Fixes the issue where players werent receiving correct change when paying with larger denominations.

Problem

When a player paid with a gold block (9g) for items costing 1-8g, they received incorrect change:

• 1g purchase: Got 7 ingots instead of 8
• 4g purchase: Got 1 ingot instead of 5
• 5-8g purchase: Got 0 ingots instead of 1-4

Solution

Complete rewrite of the ItemCalculations.calculation() method with a cleaner algorithm:

1. First pass: try to pay with exact denominations
2. Second pass: break down smallest larger denomination if needed
3. Calculate and provide correct change

Also fixed a bug in CalculationData.provideMaterials() where the default value was incorrect.

Files Changed

• Core/src/net/tnemc/core/currency/calculations/ItemCalculations.java
• Core/src/net/tnemc/core/currency/calculations/CalculationData.java

Testing

Tested with all reported scenarios that are now returning correct change amounts.

[CLAassistant]

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