money: day-by-day forecast with real payment dates

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

src/lib/money-tracker/scenarios.test.ts

@@ -76,29 +76,73 @@ describe('runScenario', () => {
 		moveCostEuros: 0,
 		bonusPercentOfTarget: 0
 	};
-	it('runs monthly to the end date and starts from today', () => {
+	type Point = { date: string; cash: number; invested: number; total: number };
+	const on = (points: Point[], date: string) => points.find((point) => point.date === date)!;
+	it('runs day by day to the end date and starts from today', () => {
 		const result = runScenario(inputs, flat);
 		expect(result.points[0]).toMatchObject({ date: '2026-10-24', total: 350000 });
+		expect(result.points[1].date).toBe('2026-10-25');
 		expect(result.end.date).toBe('2030-12-31');
-		expect(result.points).toHaveLength(51);
+		expect(result.points).toHaveLength(1530);
 		expect(result.years.map((row) => row.year)).toEqual([2026, 2027, 2028, 2029, 2030]);
 	});
-	it('fills the buffer before investing and counts recurring income and costs', () => {
-		const result = runScenario(inputs, flat);
-		const november = result.points[1];
-		expect(november.cash).toBe(500000);
-		// 300k salary + 10k benefit + 28k one-off + 13th month 3/12 − 3k gym − 90k pre-move household.
-		expect(november.total).toBeCloseTo(350000 + 300000 + 10000 + 28000 + 51250 - 3000 - 90000, 0);
+	it('pays salary on payday, sweeps the excess the day after and counts recurring income and costs', () => {
+		const points = runScenario(inputs, flat).points;
+		// Without history the contract payday (the 25th) is used; €900 pre-move household is
+		// spread at €30 a day in November.
+		expect(on(points, '2026-11-25').total - on(points, '2026-11-24').total).toBeCloseTo(
+			300000 + 51250 - 3000,
+			0
+		);
+		// The benefit (paid on the 1st, a Sunday) moves to Monday.
+		expect(on(points, '2026-11-02').total - on(points, '2026-11-01').total).toBeCloseTo(
+			10000 - 3000,
+			0
+		);
+		expect(on(points, '2026-11-25').cash).toBeGreaterThan(500000);
+		expect(on(points, '2026-11-26').cash).toBe(500000);
+		// Rest of October: 7/31 of the €900 pre-move household. November: 300k salary + 10k benefit
+		// + 28k one-off + 13th month 3/12 − 3k gym − 90k pre-move household.
+		expect(on(points, '2026-11-30').total).toBeCloseTo(
+			350000 - (90000 * 7) / 31 + 300000 + 10000 + 28000 + 51250 - 3000 - 90000,
+			0
+		);
 	});
-	it('pays contract extras in May (holiday pay) and August (bonus)', () => {
-		const delta = (points: { total: number }[], index: number) =>
-			points[index].total - points[index - 1].total;
+	it('pays contract extras on payday in May (holiday pay) and August (bonus)', () => {
 		const flatRun = runScenario(inputs, flat).points;
-		// Index 7 is May 2027: holiday pay 8/12 of €1,950.
-		expect(delta(flatRun, 7) - delta(flatRun, 6)).toBeCloseTo(130000, 0);
+		const jump = (points: typeof flatRun, date: string, before: string) =>
+			on(points, date).total - on(points, before).total;
+		// Holiday pay 8/12 of €1,950 on top of the salary.
+		expect(jump(flatRun, '2027-05-25', '2027-05-24')).toBeCloseTo(300000 + 130000, 0);
+		expect(jump(flatRun, '2027-05-24', '2027-05-23')).toBeCloseTo(0, 0);
 		const bonus = runScenario(inputs, { ...flat, bonusPercentOfTarget: 100 }).points;
-		// Index 10 is August 2027: the first bonus, €850.
-		expect(delta(bonus, 10) - delta(flatRun, 10)).toBeCloseTo(85000, 0);
+		expect(on(bonus, '2027-08-24').total - on(flatRun, '2027-08-24').total).toBeCloseTo(0, 0);
+		expect(on(bonus, '2027-08-25').total - on(flatRun, '2027-08-25').total).toBeCloseTo(85000, 0);
+	});
+	it('uses the payday from history and moves it before a weekend', () => {
+		const withHistory = scenarioInputs({
+			accounts,
+			balances: new Map([[1, 200000]]),
+			recurring: [
+				{ name: 'Cargill salary', amountCents: 300000, cadence: 'monthly', accountId: 1 }
+			],
+			forecasts: [],
+			futureTransactions: [],
+			history: [
+				{ date: '2026-09-21', amountCents: 298000, description: 'Salaris Cargill' },
+				{ date: '2026-10-21', amountCents: 298653, description: 'Salaris Cargill' }
+			],
+			today: '2026-10-24',
+			endDate: '2027-01-31'
+		});
+		expect(withHistory.payday?.day).toBe(21);
+		const points = runScenario(withHistory, flat).points;
+		// 21 November 2026 is a Saturday, so the salary lands on Friday the 20th.
+		expect(on(points, '2026-11-20').total - on(points, '2026-11-19').total).toBeGreaterThan(300000);
+		expect(on(points, '2026-12-21').total - on(points, '2026-12-20').total).toBeCloseTo(
+			300000 - 90000 / 31,
+			0
+		);
 	});
 	it('orders the default scenarios from pessimistic to optimistic', () => {
 		const [pessimistic, realistic, optimistic] = (
@@ -148,7 +192,7 @@ describe('runScenario', () => {
 			hopGapMonths: 4,
 			salaryCapEuros: 60000
 		});
-		expect(result.points).toHaveLength(1201);
+		expect(result.points).toHaveLength(36525);
 		const byYear = new Map(result.years.map((row) => [row.year, row]));
 		expect(byYear.get(2029)!.events).toEqual(['Between jobs (4 mo)']);
 		expect(byYear.get(2030)!.events).toEqual(['New job']);