test: cover exception narrowing behavior

[simPod]

Summary

Adds behavior-level PHPStan assertions for exception narrowing in both Brick extension packages.

The tests pair positive and negative cases so regressions are visible when an exception is incorrectly removed or stops being removed.

Money coverage includes:

• factory methods: number format, unknown currency, and rounding exceptions
• arithmetic and comparison methods: parsing, rounding, division-by-zero, currency/context mismatch residuals
• conversion methods: unknown currency, number format, invalid exchange rate, and rounding residuals
• MoneyBag and CurrencyConverter currency handling

Math coverage includes:

• factory methods: parsing and division-by-zero residuals
• conversion methods: no-op conversions, integer overflow, and rounding residuals
• operation methods: parsing, division-by-zero, and residual operation exceptions
• rounding-mode methods: rounding, invalid scale, and negative-number residuals