feat(vacaciones): add vacation range manager screen

Add the Vacaciones manager screen per design ADR-6: an active-range
hero (name, days-remaining countdown, determinate progress bar, and a
per-alarm pause-impact line), a "PROGRAMADOS" upcoming-ranges list, an
"Add range" CTA, and a "Rangos pasados" history section. This is the
real destination WU8's Alarmas-root summary row pushes to, replacing
WU8's own temporary placeholder (_PantallaVacacionesTemporal, now
deleted).

EstadoAlarmas gains 4 pure query methods (rangoVacacionesActivo,
vacacionesProximas, vacacionesPasadas, impactoDeRango) -- read-only
over _alarmas/_vacaciones, no writes, no rescheduling, no native
bridge calls. impactoDeRango mirrors ServicioProgramacionAlarmas's own
pause predicate exactly, so the screen never disagrees with the
scheduler about which alarms are paused. ImpactoVacaciones joins
RangoVacaciones in alarma_musical.dart.

The add-range form (_EditorVacacionesSheet, _PickerButton) moved
verbatim from pantalla_alarmas.dart to its one remaining consumer.
estado_alarmas.dart's scheduling/snooze paths and the ringing screen's
dismiss guard are untouched; both test files pass unmodified.

New ARB keys (en/es only; other 11 locales are WU18's job):
vacationImpact{Paused,Continues}Label, vacationUpcomingSectionTitle,
vacationPastSectionTitle, addVacationRangeCta,
vacationNoActiveRangeHint.

lib/l10n/gen/app_localizations.dart

@@ -1874,6 +1874,42 @@ abstract class AppLocalizations {
   /// **'Próximo rango en {days} días'**
   String vacationSummaryUpcomingCountdown(int days);
 
+  /// No description provided for @vacationImpactPausedLabel.
+  ///
+  /// In es, this message translates to:
+  /// **'Pausa: {times}'**
+  String vacationImpactPausedLabel(Object times);
+
+  /// No description provided for @vacationImpactContinuesLabel.
+  ///
+  /// In es, this message translates to:
+  /// **'Sigue sonando: {times}'**
+  String vacationImpactContinuesLabel(Object times);
+
+  /// No description provided for @vacationUpcomingSectionTitle.
+  ///
+  /// In es, this message translates to:
+  /// **'PROGRAMADOS'**
+  String get vacationUpcomingSectionTitle;
+
+  /// No description provided for @vacationPastSectionTitle.
+  ///
+  /// In es, this message translates to:
+  /// **'Rangos pasados'**
+  String get vacationPastSectionTitle;
+
+  /// No description provided for @addVacationRangeCta.
+  ///
+  /// In es, this message translates to:
+  /// **'Añadir rango'**
+  String get addVacationRangeCta;
+
+  /// No description provided for @vacationNoActiveRangeHint.
+  ///
+  /// In es, this message translates to:
+  /// **'No hay un rango de vacaciones activo ahora mismo.'**
+  String get vacationNoActiveRangeHint;
+
   /// No description provided for @vacationsDefaultName.
   ///
   /// In es, this message translates to:

lib/l10n/gen/app_localizations_ar.dart

@@ -1018,6 +1018,29 @@ class AppLocalizationsAr extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => 'إجازات';
 

lib/l10n/gen/app_localizations_bn.dart

@@ -1025,6 +1025,29 @@ class AppLocalizationsBn extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => 'ছুটি';
 

lib/l10n/gen/app_localizations_de.dart

@@ -1026,6 +1026,29 @@ class AppLocalizationsDe extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => 'Ferien';
 

lib/l10n/gen/app_localizations_en.dart

@@ -1020,6 +1020,28 @@ class AppLocalizationsEn extends AppLocalizations {
     return 'Next range in $days days';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Paused: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Still ringing: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'SCHEDULED';
+
+  @override
+  String get vacationPastSectionTitle => 'Past ranges';
+
+  @override
+  String get addVacationRangeCta => 'Add range';
+
+  @override
+  String get vacationNoActiveRangeHint => 'No active vacation range right now.';
+
   @override
   String get vacationsDefaultName => 'Vacation';
 

lib/l10n/gen/app_localizations_es.dart

@@ -1024,6 +1024,29 @@ class AppLocalizationsEs extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => 'Vacaciones';
 

lib/l10n/gen/app_localizations_fr.dart

@@ -1030,6 +1030,29 @@ class AppLocalizationsFr extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => 'Vacances';
 

lib/l10n/gen/app_localizations_hi.dart

@@ -1021,6 +1021,29 @@ class AppLocalizationsHi extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => 'छुट्टियाँ';
 

lib/l10n/gen/app_localizations_id.dart

@@ -1025,6 +1025,29 @@ class AppLocalizationsId extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => 'Liburan';
 

lib/l10n/gen/app_localizations_it.dart

@@ -1026,6 +1026,29 @@ class AppLocalizationsIt extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => 'Vacanze';
 

lib/l10n/gen/app_localizations_ja.dart

@@ -994,6 +994,29 @@ class AppLocalizationsJa extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => '休暇';
 

lib/l10n/gen/app_localizations_pt.dart

@@ -1023,6 +1023,29 @@ class AppLocalizationsPt extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => 'Férias';
 

lib/l10n/gen/app_localizations_ru.dart

@@ -1025,6 +1025,29 @@ class AppLocalizationsRu extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => 'Отпуск';
 

lib/l10n/gen/app_localizations_zh.dart

@@ -990,6 +990,29 @@ class AppLocalizationsZh extends AppLocalizations {
     return 'Próximo rango en $days días';
   }
 
+  @override
+  String vacationImpactPausedLabel(Object times) {
+    return 'Pausa: $times';
+  }
+
+  @override
+  String vacationImpactContinuesLabel(Object times) {
+    return 'Sigue sonando: $times';
+  }
+
+  @override
+  String get vacationUpcomingSectionTitle => 'PROGRAMADOS';
+
+  @override
+  String get vacationPastSectionTitle => 'Rangos pasados';
+
+  @override
+  String get addVacationRangeCta => 'Añadir rango';
+
+  @override
+  String get vacationNoActiveRangeHint =>
+      'No hay un rango de vacaciones activo ahora mismo.';
+
   @override
   String get vacationsDefaultName => '假期';