T3: Decimal for money — all monetary fields migrated from float
- All domain monetary fields now use Decimal:
- Account.balance, Asset.value, Asset.growth_rate
- Liability.balance, Liability.interest, Liability.payment
- Transaction.amount, RecurringCashflow.amount
- ExchangeRate.rate
- ForecastScenario.income_multiplier, expense_multiplier, growth_multiplier
- CurrencyConverter: all arithmetic in Decimal, quantize to 0.01 with ROUND_HALF_UP
- ForecastService: Decimal arithmetic throughout (income, expenses, balance, growth, liability cost)
- ScenarioService: Decimal multipliers, deepcopy safe with Decimal fields
- assistant.py: _DecimalEncoder for json.dumps (Decimal -> str in JSON)
Pydantic v2 + Decimal:
- model_dump(mode='json') converts Decimal to str (JSON-safe)
- model_validate() parses str back to Decimal
- Round-trip preserves precision (100.50 stays 100.50)
Tests: 63/63 pass.
oqyude
363d440d53