export: branding en los tres estilos (logo, wordmark degradado, tagline)

- Logo real de la app en el header de los 3 estilos (antes solo en el
  default, y pequeno) y en el footer junto a un wordmark MealMood en
  degradado coral->verde con tagline localizada en cursiva
- "Powered by MealMood" y "Scan me" estaban hardcodeados en ingles;
  ahora share_footer_tagline y share_footer_scan en 6 idiomas
- Titulo del header default con el mismo degradado; QR con borde coral

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

MealMood/Resources/de.lproj/Localizable.strings

@@ -431,3 +431,5 @@
 "share_export_preview_title" = "Woche exportieren";
 "share_export_preview_rendering" = "Vorschau wird erstellt…";
 "share_export_share_button" = "Teilen";
+"share_footer_tagline" = "Deine Woche, mit Liebe geplant";
+"share_footer_scan" = "Scann mich";

MealMood/Resources/en.lproj/Localizable.strings

@@ -431,3 +431,5 @@
 "share_export_preview_title" = "Export week";
 "share_export_preview_rendering" = "Generating preview…";
 "share_export_share_button" = "Share";
+"share_footer_tagline" = "Your week, planned with love";
+"share_footer_scan" = "Scan me";

MealMood/Resources/es.lproj/Localizable.strings

@@ -431,3 +431,5 @@
 "share_export_preview_title" = "Exportar semana";
 "share_export_preview_rendering" = "Generando vista previa…";
 "share_export_share_button" = "Compartir";
+"share_footer_tagline" = "Tu semana, planificada con cariño";
+"share_footer_scan" = "Escanéame";

MealMood/Resources/fr.lproj/Localizable.strings

@@ -431,3 +431,5 @@
 "share_export_preview_title" = "Exporter la semaine";
 "share_export_preview_rendering" = "Génération de l'aperçu…";
 "share_export_share_button" = "Partager";
+"share_footer_tagline" = "Votre semaine, planifiée avec amour";
+"share_footer_scan" = "Scannez-moi";

MealMood/Resources/it.lproj/Localizable.strings

@@ -431,3 +431,5 @@
 "share_export_preview_title" = "Esporta settimana";
 "share_export_preview_rendering" = "Generazione anteprima…";
 "share_export_share_button" = "Condividi";
+"share_footer_tagline" = "La tua settimana, pianificata con amore";
+"share_footer_scan" = "Scansionami";

MealMood/Resources/pt-BR.lproj/Localizable.strings

@@ -431,3 +431,5 @@
 "share_export_preview_title" = "Exportar semana";
 "share_export_preview_rendering" = "Gerando pré-visualização…";
 "share_export_share_button" = "Compartilhar";
+"share_footer_tagline" = "Sua semana, planejada com carinho";
+"share_footer_scan" = "Escaneie-me";

MealMood/Views/Home/WeekPlanShareView.swift

@@ -185,12 +185,17 @@ struct WeekPlanShareView: View {
 
     private var defaultHeader: some View {
         HStack(alignment: .center, spacing: 24) {
-            AppIconPlaceholder(size: 84)
+            AppIconPlaceholder(size: 104)
 
             VStack(alignment: .leading, spacing: 6) {
                 Text(exportHeaderTitle)
                     .font(.system(size: 52, weight: .bold, design: .rounded))
-                    .foregroundColor(.mealMoodTextPrimary)
+                    .foregroundStyle(
+                        LinearGradient(
+                            colors: [Color.mealMoodCoral, Color(hex: "#3F7A64")],
+                            startPoint: .leading, endPoint: .trailing
+                        )
+                    )
                 Text(plan.weekStartDate.formattedWeekRange())
                     .font(.system(size: 28, weight: .semibold, design: .rounded))
                     .foregroundColor(Color(hex: "#5D645F"))
@@ -213,7 +218,9 @@ struct WeekPlanShareView: View {
     }
 
     private var elegantHeader: some View {
-        VStack(spacing: 8) {
+        VStack(spacing: 10) {
+            MealMoodLogoMark(size: 96)
+
             Text(plan.weekStartDate.formattedWeekRange())
                 .font(.custom("Didot", size: exportStyle == .vertical ? 126 : 108))
                 .foregroundColor(Color(hex: "#30473F"))
@@ -430,13 +437,24 @@ struct WeekPlanShareView: View {
     }
 
     private var footerBlock: some View {
-        HStack(alignment: .center, spacing: 20) {
-            VStack(alignment: .leading, spacing: 6) {
-                Text("Powered by MealMood")
-                    .font(.system(size: 30, weight: .bold, design: .rounded))
-                    .foregroundColor(Color(hex: "#3A3A3A"))
+        HStack(alignment: .center, spacing: 24) {
+            MealMoodLogoMark(size: 118)
+
+            VStack(alignment: .leading, spacing: 5) {
+                Text(verbatim: "MealMood")
+                    .font(.system(size: 44, weight: .heavy, design: .rounded))
+                    .foregroundStyle(
+                        LinearGradient(
+                            colors: [Color.mealMoodCoral, Color(hex: "#3F7A64")],
+                            startPoint: .leading, endPoint: .trailing
+                        )
+                    )
+                Text(String(localized: "share_footer_tagline"))
+                    .font(.system(size: 26, weight: .semibold, design: .rounded))
+                    .italic()
+                    .foregroundColor(Color(hex: "#5D645F"))
                 Text(shareURL)
-                    .font(.system(size: 24, weight: .semibold, design: .rounded))
+                    .font(.system(size: 22, weight: .semibold, design: .rounded))
                     .foregroundColor(Color(hex: "#588A77"))
             }
 
@@ -452,7 +470,11 @@ struct WeekPlanShareView: View {
                         .padding(10)
                         .background(Color.white)
                         .clipShape(RoundedRectangle(cornerRadius: 18))
-                    Text("Scan me")
+                        .overlay(
+                            RoundedRectangle(cornerRadius: 18)
+                                .stroke(Color.mealMoodCoral.opacity(0.35), lineWidth: 1)
+                        )
+                    Text(String(localized: "share_footer_scan"))
                         .font(.system(size: 18, weight: .semibold, design: .rounded))
                         .foregroundColor(.mealMoodTextSecondary)
                 }