1.4.1 (build 42): contribución por snapshot, fixes Period vs Period y navegación iPad

- 151: contribución editable por snapshot en cualquier modo (quitado gate detailed)
  con diálogo de propagación al editar: solo este / adelante / atrás / todos
  (SnapshotRepository.propagateContribution, SnapshotFormViewModel.contributionChanged)
- 148: Period vs Period mostraba mal el último mes del period B — la agrupación usaba
  chartMonth(for:) que aplicaba el grace-period del check-in a snapshots históricos;
  ahora agrupa por mes calendario crudo
- 152: iPad Sources no saltaba entre fuentes — añadido .id() al SourceDetailView para
  recrear el StateObject al cambiar de selección
- 146/147: Year vs Year con forecast del año en curso (asterisco de estimado) y KPIs
  arriba / detalle debajo
- 145: card de contribución mensual en SourceDetailView
- Nuevas claves snapshot_contribution_propagate_* en los 7 idiomas

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

PortfolioJournal/ViewModels/DashboardViewModel.swift

@@ -1,6 +1,7 @@
 import Foundation
 import Combine
 import CoreData
+import SwiftUI
 
 @MainActor
 class DashboardViewModel: ObservableObject {
@@ -646,6 +647,82 @@ class DashboardViewModel: ObservableObject {
         sourcesNeedingUpdate.count
     }
 
+    var insights: [PortfolioInsight] {
+        var result: [PortfolioInsight] = []
+        guard portfolioSummary.totalValue > 0 else { return result }
+        let total = portfolioSummary.totalValue
+
+        // 1. Milestone approaching (within 10% of next round milestone)
+        let milestones: [Decimal] = [1000, 2500, 5000, 10000, 25000, 50000,
+                                      100000, 250000, 500000, 1_000_000,
+                                      2_500_000, 5_000_000, 10_000_000]
+        if let next = milestones.first(where: { $0 > total }) {
+            let pct = NSDecimalNumber(decimal: total / next).doubleValue
+            if pct >= 0.90 {
+                let gap = next - total
+                let gapStr = CurrencyFormatter.format(gap, style: .currency, maximumFractionDigits: 0)
+                let msStr = CurrencyFormatter.format(next, style: .currency, maximumFractionDigits: 0)
+                result.append(PortfolioInsight(
+                    id: "milestone",
+                    systemImage: "flag.checkered",
+                    title: String(localized: "insight_milestone_title"),
+                    value: String(format: String(localized: "insight_milestone_value"), gapStr, msStr),
+                    accentColor: .orange
+                ))
+            }
+        }
+
+        // 2. Year-to-date performance
+        let ytdPct = portfolioSummary.yearChangePercentage
+        if abs(ytdPct) >= 0.1 {
+            let icon = ytdPct >= 0 ? "arrow.up.right.circle.fill" : "arrow.down.right.circle.fill"
+            result.append(PortfolioInsight(
+                id: "ytd",
+                systemImage: icon,
+                title: String(localized: "insight_ytd_title"),
+                value: String(format: "%+.1f%%", ytdPct),
+                accentColor: ytdPct >= 0 ? .positiveGreen : .negativeRed
+            ))
+        }
+
+        // 3. All-time market gains
+        let gains = portfolioSummary.allTimeReturn
+        if gains > 0 {
+            let gainStr = CurrencyFormatter.format(gains, style: .currency, maximumFractionDigits: 0)
+            result.append(PortfolioInsight(
+                id: "market_gains",
+                systemImage: "chart.line.uptrend.xyaxis",
+                title: String(localized: "insight_market_gains_title"),
+                value: String(format: String(localized: "insight_market_gains_value"), gainStr),
+                accentColor: .appPrimary
+            ))
+        }
+
+        // 4. Tracking streak (>= 3 months)
+        if updateStreak >= 3 {
+            result.append(PortfolioInsight(
+                id: "streak",
+                systemImage: "flame.fill",
+                title: String(localized: "insight_streak_title"),
+                value: String(format: String(localized: "insight_streak_value"), updateStreak),
+                accentColor: .orange
+            ))
+        }
+
+        // 5. Forecast
+        if let forecast = portfolioForecast, forecast.forecastValue > total {
+            result.append(PortfolioInsight(
+                id: "forecast",
+                systemImage: "wand.and.stars",
+                title: String(localized: "insight_forecast_title"),
+                value: "\(forecast.formattedForecastValue) · \(forecast.formattedForecastDate)",
+                accentColor: .purple
+            ))
+        }
+
+        return result
+    }
+
     var topCategories: [CategoryMetrics] {
         Array(categoryMetrics.prefix(5))
     }