Rediseño Charts iPad, zoom en gráficas, eliminación de Focus Mode y fixes de rendimiento

Charts iPad (rediseño):
- Fila de KPIs sobre el chart: Total Value, Period Return, CAGR, Volatility y Max
  Drawdown del rango activo (nuevo ChartsViewModel.portfolioMetrics, calculado sobre
  los TOTALES MENSUALES AGREGADOS — pasar snapshots multi-source crudos a
  calculateMetrics producía KPIs absurdos)
- Sidebar (248pt) con tiles de chart type en grid 2 col agrupados por sección:
  Overview / Analyze / Risk / Forecast, con candado premium y accesibilidad
- Selector de periodo como Picker segmentado nativo en la cabecera del chart
  (fuera del sidebar); título + descripción del chart visibles
- Eliminado sheet de paywall duplicado del layout iPad

Zoom (todas las series temporales):
- Nuevo ChartZoom.swift: pinch + botones +/- y reset (HIG: el gesto nunca es el
  único camino), chartScrollableAxes + chartXVisibleDomain al hacer zoom
- Integrado en Evolution, Contributions, Rolling 12M, Cashflow, Drawdown y Volatility

Focus Mode eliminado (todo siempre disponible):
- Fuera el toggle de Dashboard/Charts/Settings/Onboarding y los 6 @AppStorage
- Todos los chart types siempre visibles; variantes completas en SourceDetail/SourceList
- Home: Total Portfolio Value muestra SIEMPRE el cambio desde el último check-in
- PeriodReturnsCard siempre visible

Rendimiento y bugs (de la auditoría):
- El cache de snapshots ya no se invalida al cambiar solo de chart type/rango/breakdown
- calculateAnnualizedGrowth y el forecast a 12 meses ahora componen (la aproximación
  lineal sobreestimaba con historiales cortos)
- Drawdown sin force unwrap; simulador: rama muerta reemplazada por preservación
  real de las asignaciones simuladas del usuario
- UITest de captura de Charts con manejo del alert de notificaciones

12 strings nuevas localizadas en los 7 idiomas.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015qUZrBusG82T37R7PeokqJ

PortfolioJournal/ViewModels/ChartsViewModel.swift

@@ -87,16 +87,6 @@ class ChartsViewModel: ObservableObject {
         }
     }
 
-    func availableChartTypes(calmModeEnabled: Bool) -> [ChartType] {
-        let types: [ChartType] = calmModeEnabled
-            ? [.evolution, .allocation, .performance, .contributions, .comparison, .periodComparison]
-            : ChartType.allCases
-        if !types.contains(selectedChartType) {
-            selectedChartType = .evolution
-        }
-        return types
-    }
-
     // MARK: - Published Properties
 
     @Published var selectedChartType: ChartType = .evolution
@@ -124,6 +114,8 @@ class ChartsViewModel: ObservableObject {
     /// Months of data hidden by the free-tier 12-month history limit (0 for premium).
     /// Drives the "unlock X more months" teaser in the charts screen.
     @Published var hiddenHistoryMonths: Int = 0
+    /// Portfolio-level metrics for the active time range — feeds the iPad KPI header.
+    @Published var portfolioMetrics: InvestmentMetrics = .empty
     @Published var yoySelectedYears: Set<Int> = []
 
     struct YearSeries: Identifiable {
@@ -311,6 +303,13 @@ class ChartsViewModel: ObservableObject {
                     self.lastBreakdown != selectedBreakdown
 
                 if hasChanges {
+                    // Raw snapshots only depend on the data selection (sources/account/
+                    // category) — switching chart type, range or breakdown reuses them.
+                    let dataSelectionChanged = self.lastCategoryId != category?.id ||
+                        self.lastSourceId != selectedSource?.id ||
+                        self.lastSourceIds != sourceIds ||
+                        self.lastAccountId != safeSelectedAccountId ||
+                        self.lastShowAllAccounts != showAll
                     self.lastChartType = chartType
                     self.lastTimeRange = timeRange
                     self.lastCategoryId = category?.id
@@ -319,7 +318,9 @@ class ChartsViewModel: ObservableObject {
                     self.lastAccountId = safeSelectedAccountId
                     self.lastShowAllAccounts = showAll
                     self.lastBreakdown = selectedBreakdown
-                    self.cachedSnapshots = nil // Invalidate cache on meaningful changes
+                    if dataSelectionChanged {
+                        self.cachedSnapshots = nil
+                    }
                     self.updateChartData(chartType: chartType, category: category, timeRange: timeRange)
                 }
             }
@@ -468,6 +469,9 @@ class ChartsViewModel: ObservableObject {
             snapshots = snapshots.filter { $0.date >= cutoffDate }
         }
 
+        // Portfolio KPIs for the visible range (iPad header)
+        portfolioMetrics = computePortfolioKPIs(from: snapshots)
+
         let completedSnapshots = filterSnapshotsForCharts(
             sources: sources,
             snapshots: snapshots
@@ -1072,7 +1076,11 @@ class ChartsViewModel: ObservableObject {
             return
         }
 
-        var peak = totals.first!.totalValue
+        guard let firstTotal = totals.first else {
+            drawdownData = []
+            return
+        }
+        var peak = firstTotal.totalValue
         var data: [(date: Date, drawdown: Double)] = []
 
         for point in totals {
@@ -1378,12 +1386,16 @@ class ChartsViewModel: ObservableObject {
             ))
         }
 
-        // Only update if sources changed (avoid resetting sliders on normal refresh)
+        // Only reset sliders when the source set actually changed; otherwise refresh
+        // current percentages but keep the user's simulated allocations.
         if simulatorSources.map({ $0.id }) != simulatorNew.map({ $0.id }) {
             simulatorSources = simulatorNew
         } else {
-            // Update currentPct but preserve simulatedPct
-            simulatorSources = simulatorNew
+            simulatorSources = zip(simulatorSources, simulatorNew).map { old, new in
+                var updated = new
+                updated.simulatedPct = old.simulatedPct
+                return updated
+            }
         }
 
         recalculateSimulatedLine(sources: simulatorSources, sourceMonthlyValues: sourceMonthlyValues, allMonths: allMonths)
@@ -1540,6 +1552,65 @@ class ChartsViewModel: ObservableObject {
         periodComparisonData = result
     }
 
+    /// Portfolio-level KPIs computed over the AGGREGATED monthly totals.
+    /// Feeding raw multi-source snapshots into CalculationService.calculateMetrics
+    /// produced nonsense (first/last belong to different sources) — the aggregate
+    /// series is the correct basis for portfolio return, CAGR, volatility and drawdown.
+    private func computePortfolioKPIs(from snapshots: [Snapshot]) -> InvestmentMetrics {
+        let totals = monthlyTotals(from: snapshots)
+        guard totals.count >= 2,
+              let first = totals.first, let last = totals.last,
+              first.totalValue > 0 else {
+            let value = totals.last?.totalValue ?? 0
+            return InvestmentMetrics(
+                totalValue: value, totalContributions: 0,
+                absoluteReturn: 0, percentageReturn: 0,
+                cagr: 0, twr: 0, volatility: 0, maxDrawdown: 0, sharpeRatio: 0,
+                bestMonth: nil, worstMonth: nil, winRate: 0, averageMonthlyReturn: 0,
+                startDate: totals.first?.date, endDate: totals.last?.date,
+                totalMonths: totals.count
+            )
+        }
+
+        let absolute = last.totalValue - first.totalValue
+        let percentage = (absolute / first.totalValue) * 100
+        let cagr = calculationService.calculateCAGR(
+            startValue: first.totalValue, endValue: last.totalValue,
+            startDate: first.date, endDate: last.date
+        )
+
+        // Monthly returns over the aggregate series
+        var monthlyReturns: [InvestmentMetrics.MonthlyReturn] = []
+        for i in 1..<totals.count where totals[i - 1].totalValue > 0 {
+            let r = NSDecimalNumber(
+                decimal: (totals[i].totalValue - totals[i - 1].totalValue) / totals[i - 1].totalValue
+            ).doubleValue * 100
+            monthlyReturns.append(.init(date: totals[i].date, returnPercentage: r))
+        }
+        let volatility = calculationService.calculateVolatility(monthlyReturns: monthlyReturns)
+        let maxDrawdown = calculationService.calculateMaxDrawdown(values: totals.map { $0.totalValue })
+        let avgMonthly = monthlyReturns.isEmpty
+            ? 0 : monthlyReturns.map { $0.returnPercentage }.reduce(0, +) / Double(monthlyReturns.count)
+        let sharpe = calculationService.calculateSharpeRatio(
+            averageReturn: avgMonthly * 12, volatility: volatility, riskFreeRate: 2.0
+        )
+
+        return InvestmentMetrics(
+            totalValue: last.totalValue,
+            totalContributions: 0,
+            absoluteReturn: absolute,
+            percentageReturn: percentage,
+            cagr: cagr, twr: 0,
+            volatility: volatility, maxDrawdown: maxDrawdown, sharpeRatio: sharpe,
+            bestMonth: monthlyReturns.max(by: { $0.returnPercentage < $1.returnPercentage }),
+            worstMonth: monthlyReturns.min(by: { $0.returnPercentage < $1.returnPercentage }),
+            winRate: calculationService.calculateWinRate(monthlyReturns: monthlyReturns),
+            averageMonthlyReturn: avgMonthly,
+            startDate: first.date, endDate: last.date,
+            totalMonths: totals.count
+        )
+    }
+
     private func monthlyTotals(from snapshots: [Snapshot]) -> [(date: Date, totalValue: Decimal)] {
         let groupedByMonth = Dictionary(grouping: snapshots) { snapshot -> Date in
             chartMonthStart(for: snapshot.date)