The wealth forecast now runs per day instead of per month, so it shows the
same sawtooth as the actual history:
- recurring items hit on the day the bank history shows (most common day of
the last four months, clamped to month end), else their start date
- "every N weeks" items (Basic-Fit, haircut) run on an exact N-day cadence
from the last charge; yearly items on their renewal date
- salary and its extras (holiday pay in May, 13th month in November, bonus,
settlement) land on the payday from history (contract 25th as fallback),
moved to the Friday before a weekend; toeslagen move to the Monday after
- variable budgets are spread per day, the vacation budget over Jul-Aug
- excess above the buffer is invested the day after payday; returns
compound daily
- long horizons stay fast (~35 ms for 100 years): the chart thins each
pixel bucket to its low and high
