reglas: el panel explica que se incumple y como arreglarlo; stats por etiqueta

- RuleViolation.reasons: el motor devuelve ahora QUE regla rompe cada
  asignacion (repetido en la semana, maximo por semana superado, no
  consecutivo, no mismo dia, solo comida/cena, solo entre semana o fin
  de semana) con su etiqueta y limite
- Panel de avisos: bloque con cada regla rota en lenguaje claro + una
  sugerencia de que hacer, y boton nuevo "Cambiar plato" que abre el
  selector de ese hueco (antes solo se podia quitar o ignorar)
- Estadisticas: matriz "Etiquetas por tipo de comida" (p.ej. cuantas
  cenas son de pescado) y "Platos por etiqueta" del catalogo
- Tests: 4 casos de las razones de incumplimiento; harness que renderiza
  las secciones nuevas de stats a /tmp/stats_render.png
- Strings en 6 idiomas

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013H6bXqGX1ygwib1Dm3n3UG

MealMoodTests/AutocompleteEngineTests.swift

@@ -81,3 +81,69 @@ final class AutocompleteEngineTests: XCTestCase {
         XCTAssertEqual(preferred.id, duplicateWithDish.id)
     }
 }
+
+/// The violations panel explains *which* rule is broken; these cover the
+/// reason detection that feeds it.
+final class ViolationReasonsTests: XCTestCase {
+
+    private func makePlan(slots: [(day: Int, meal: String, dishId: UUID?)]) -> WeekPlan {
+        let plan = WeekPlan(weekStartDate: Date().startOfWeek())
+        for s in slots {
+            let slot = MealSlot(dayOfWeek: s.day, mealType: s.meal, dishId: s.dishId)
+            slot.weekPlan = plan
+            plan.slotList.append(slot)
+        }
+        return plan
+    }
+
+    func testMaxPerWeekExceededIsReported() {
+        let tag = Tag(name: "Pasta", color: "#FF0000", maxPerWeek: 1)
+        let dish = Dish(name: "Espaguetis", tagIds: [tag.id])
+        let other = Dish(name: "Macarrones", tagIds: [tag.id])
+        let plan = makePlan(slots: [(0, "dinner", dish.id), (1, "dinner", other.id)])
+        let slot = plan.slotList[0]
+
+        let reasons = AutocompleteEngine.reasons(
+            dish: dish, slot: slot, plan: plan,
+            tagMap: [tag.id: tag], dishMap: [dish.id: dish, other.id: other]
+        )
+        XCTAssertTrue(reasons.contains { $0.kind == .maxPerWeek && $0.limit == 1 },
+                      "Two pasta dishes with max 1/week must report maxPerWeek")
+    }
+
+    func testMealTypeRestrictionIsReported() {
+        let tag = Tag(name: "Ligero", color: "#00FF00", mealTypeRestriction: "dinner")
+        let dish = Dish(name: "Ensalada", tagIds: [tag.id])
+        let plan = makePlan(slots: [(0, "lunch", dish.id)])
+
+        let reasons = AutocompleteEngine.reasons(
+            dish: dish, slot: plan.slotList[0], plan: plan,
+            tagMap: [tag.id: tag], dishMap: [dish.id: dish]
+        )
+        XCTAssertTrue(reasons.contains { $0.kind == .mealTypeOnly && $0.restriction == "dinner" },
+                      "A dinner-only tag placed at lunch must report mealTypeOnly")
+    }
+
+    func testRepeatedDishInWeekIsReported() {
+        let dish = Dish(name: "Tortilla")
+        let plan = makePlan(slots: [(0, "dinner", dish.id), (3, "dinner", dish.id)])
+
+        let reasons = AutocompleteEngine.reasons(
+            dish: dish, slot: plan.slotList[0], plan: plan,
+            tagMap: [:], dishMap: [dish.id: dish]
+        )
+        XCTAssertTrue(reasons.contains { $0.kind == .repeatedInWeek })
+    }
+
+    func testCompliantDishHasNoReasons() {
+        let tag = Tag(name: "Pescado", color: "#0000FF", maxPerWeek: 2)
+        let dish = Dish(name: "Merluza", tagIds: [tag.id])
+        let plan = makePlan(slots: [(0, "dinner", dish.id)])
+
+        let reasons = AutocompleteEngine.reasons(
+            dish: dish, slot: plan.slotList[0], plan: plan,
+            tagMap: [tag.id: tag], dishMap: [dish.id: dish]
+        )
+        XCTAssertTrue(reasons.isEmpty, "A dish within its limits must not report violations")
+    }
+}

MealMoodTests/DateHelpersTests.swift

@@ -105,3 +105,57 @@ final class DateHelpersTests: XCTestCase {
     }
 }
 
+
+/// Renders the stats screen with sample data to /tmp so the new sections can
+/// be reviewed as an image.
+final class StatsRenderTests: XCTestCase {
+
+    @MainActor
+    func testRenderStats() throws {
+        let tags = [
+            Tag(name: "Pasta", nameEN: "Pasta", color: "#E8A87C"),
+            Tag(name: "Pescado", nameEN: "Fish", color: "#7CB7E8"),
+            Tag(name: "Verdura", nameEN: "Veggie", color: "#8CD790"),
+            Tag(name: "Carne", nameEN: "Meat", color: "#E87C7C")
+        ]
+        let dishes: [Dish] = [
+            Dish(name: "Espaguetis", tagIds: [tags[0].id]),
+            Dish(name: "Lasaña", tagIds: [tags[0].id, tags[3].id]),
+            Dish(name: "Merluza", tagIds: [tags[1].id]),
+            Dish(name: "Salmón", tagIds: [tags[1].id]),
+            Dish(name: "Ensalada", tagIds: [tags[2].id]),
+            Dish(name: "Pollo asado", tagIds: [tags[3].id]),
+            Dish(name: "Crema de calabaza", tagIds: [tags[2].id])
+        ]
+        var plans: [WeekPlan] = []
+        for week in 0..<3 {
+            let plan = WeekPlan(weekStartDate: Date().startOfWeek().addingDays(-7 * week))
+            var i = week
+            for day in 0...4 {
+                for meal in ["lunch", "dinner"] {
+                    let slot = MealSlot(dayOfWeek: day, mealType: meal, dishId: dishes[i % dishes.count].id)
+                    slot.weekPlan = plan
+                    plan.slotList.append(slot)
+                    i += 1
+                }
+            }
+            plans.append(plan)
+        }
+
+        let view = StatsView(weekPlans: plans, allDishes: dishes, allTags: tags, language: .spanish)
+        // Render just the new sections: ImageRenderer can't draw a NavigationStack.
+        let content = VStack(alignment: .leading, spacing: 24) {
+            view.tagByMealSection
+            view.dishesPerTagSection
+        }
+        .padding(16)
+        .frame(width: 390)
+        .background(Color.mealMoodBackground)
+
+        let renderer = ImageRenderer(content: content)
+        renderer.scale = 2
+        let image = try XCTUnwrap(renderer.uiImage)
+        let data = try XCTUnwrap(image.pngData())
+        try data.write(to: URL(fileURLWithPath: "/tmp/stats_render.png"))
+    }
+}