Fixes UI iPad + diagnóstico iCloud (build 57)

Feedback del usuario en iPad:
- Allocation: gráfica de tarta → semicírculo estilo hemiciclo (parlamento).
  SemicircleAllocation con arcos dibujados a mano (SemicircleArc Shape),
  segmentos por cuota en 180°, total/selección en el centro, tap por segmento.
- Charts de Analyze (Compare, Period vs Period, Year vs Year) ahora SÍ muestran
  KPIs en la cabecera de iPad como el resto: Compare (líder/rezagado por modo),
  Period (retorno final por periodo), YoY (retorno final por año seleccionado).
- Momentum & Streaks en el sidebar del Journal (iPad, 320pt): variante compact
  — tiles en fila sin subtítulos que rompían a 3 líneas, sin bloque de logros.

iCloud:
- CKErrorPartialFailure (CKErrorDomain code 2) mostraba un mensaje opaco.
  CoreDataStack.hint(for:) recorre CKPartialErrorsByItemIDKey y clasifica el
  código dominante → hint accionable (esquema/quota/red). Settings muestra el
  hint legible sobre el detalle técnico. lastSyncErrorHint publicado. Strings ×7.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WoScpmHdVj1aUf4rAp6hbe

PortfolioJournal/Models/CoreDataStack.swift

@@ -123,6 +123,8 @@ class CoreDataStack: ObservableObject {
     @Published private(set) var lastExportDate: Date?
     @Published private(set) var isSyncing = false
     @Published private(set) var lastSyncError: String?
+    /// Human-readable, actionable explanation of the last sync error (nil if none).
+    @Published private(set) var lastSyncErrorHint: String?
 
     var lastSyncDate: Date? { lastImportDate }
 
@@ -343,6 +345,7 @@ class CoreDataStack: ObservableObject {
                 } else if let error = event.error {
                     let typeLabel = event.type == .import ? "import" : event.type == .export ? "export" : "setup"
                     self.lastSyncError = "\(typeLabel): \(Self.describeError(error))"
+                    self.lastSyncErrorHint = Self.hint(for: error)
                     print("CloudKit \(typeLabel) full error:\n\(error)\nuserInfo: \((error as NSError).userInfo)")
                 }
             }
@@ -376,6 +379,44 @@ class CoreDataStack: ObservableObject {
         return parts.joined(separator: "\n")
     }
 
+    /// Turns an opaque CloudKit error into a human-readable, actionable hint by
+    /// digging into CKPartialErrorsByItemIDKey — the per-record failures hidden
+    /// inside a CKErrorPartialFailure (code 2). The dominant underlying code
+    /// tells us the real problem: schema not deployed (unknownItem/invalidArguments)
+    /// vs. quota vs. transient network.
+    static func hint(for error: Error) -> String? {
+        let ns = error as NSError
+        // Collect all leaf CKError codes across a possible partial-failure tree.
+        var codes: [Int] = []
+        func collect(_ e: NSError) {
+            if e.domain == "CKErrorDomain", e.code != 2 { codes.append(e.code) }
+            if let partial = e.userInfo["CKPartialErrorsByItemIDKey"] as? [AnyHashable: Any] {
+                for case let sub as NSError in partial.values { collect(sub) }
+            }
+            for value in e.userInfo.values {
+                if let sub = value as? NSError, sub !== e { collect(sub) }
+            }
+        }
+        collect(ns)
+
+        // CKError codes: 14 = unknownItem, 12 = invalidArguments, 6 = partialFailure,
+        // 25 = quotaExceeded, 4 = networkFailure/unavailable, 3 = networkUnavailable,
+        // 15 = serverRejectedRequest, 26 = operationCancelled.
+        if codes.contains(14) || codes.contains(12) || codes.contains(15) {
+            return String(localized: "icloud_hint_schema")
+        }
+        if codes.contains(25) {
+            return String(localized: "icloud_hint_quota")
+        }
+        if codes.contains(3) || codes.contains(4) {
+            return String(localized: "icloud_hint_network")
+        }
+        if ns.code == 2 {
+            return String(localized: "icloud_hint_partial_generic")
+        }
+        return nil
+    }
+
     func forceReload() {
         viewContext.perform { [weak self] in
             self?.viewContext.refreshAllObjects()