feat(auto): equalizer folder in the browse tree, one toggle on playback

On-device feedback: two identical icons on the car's now-playing screen,
one of which looked dead. It worked -- but head units render custom
actions icon-first, so cycling six presets behind one static glyph was
invisible.

A monochrome icon cannot encode which of six presets is active. Android
Auto separates the idioms deliberately: custom actions for stateless
toggles, browsable lists for choosing among options.

- Playback screen keeps one action: equalizer on/off, state-aware icons
- New Ecualizador folder lists Desactivar plus the six presets by name,
  active one marked
- The preset-cycling action and its drawable are removed

Supersedes the redesign's no-equalizer-folder rule, which predated
knowing custom actions do not surface state in a car.

# Conflicts:
#	lib/l10n/app_ar.arb
#	lib/l10n/app_bn.arb
#	lib/l10n/app_de.arb
#	lib/l10n/app_en.arb
#	lib/l10n/app_es.arb
#	lib/l10n/app_fr.arb
#	lib/l10n/app_hi.arb
#	lib/l10n/app_id.arb
#	lib/l10n/app_it.arb
#	lib/l10n/app_ja.arb
#	lib/l10n/app_pt.arb
#	lib/l10n/app_ru.arb
#	lib/l10n/app_zh.arb

lib/l10n/gen/app_localizations.dart

@@ -3187,6 +3187,12 @@ abstract class AppLocalizations {
   /// In es, this message translates to:
   /// **'Todavía no pudimos revisar tus ajustes de alarma.'**
   String get alarmDiagnosticsUnavailableHint;
+
+  /// No description provided for @autoEqDisableOption.
+  ///
+  /// In es, this message translates to:
+  /// **'Desactivar'**
+  String get autoEqDisableOption;
 }
 
 class _AppLocalizationsDelegate

lib/l10n/gen/app_localizations_ar.dart

@@ -1760,4 +1760,7 @@ class AppLocalizationsAr extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'لم نتمكّن بعد من التحقق من إعدادات المنبه الخاصة بك.';
+
+  @override
+  String get autoEqDisableOption => 'تعطيل';
 }

lib/l10n/gen/app_localizations_bn.dart

@@ -1768,4 +1768,7 @@ class AppLocalizationsBn extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'আমরা এখনও আপনার অ্যালার্ম সেটিংস পরীক্ষা করতে পারিনি।';
+
+  @override
+  String get autoEqDisableOption => 'বন্ধ করুন';
 }

lib/l10n/gen/app_localizations_de.dart

@@ -1782,4 +1782,7 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'Wir konnten deine Alarmeinstellungen noch nicht prüfen.';
+
+  @override
+  String get autoEqDisableOption => 'Deaktivieren';
 }

lib/l10n/gen/app_localizations_en.dart

@@ -1762,4 +1762,7 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'We couldn\'t check your alarm settings yet.';
+
+  @override
+  String get autoEqDisableOption => 'Disable';
 }

lib/l10n/gen/app_localizations_es.dart

@@ -1778,4 +1778,7 @@ class AppLocalizationsEs extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'Todavía no pudimos revisar tus ajustes de alarma.';
+
+  @override
+  String get autoEqDisableOption => 'Desactivar';
 }

lib/l10n/gen/app_localizations_fr.dart

@@ -1788,4 +1788,7 @@ class AppLocalizationsFr extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'Nous n\'avons pas encore pu vérifier vos paramètres d\'alarme.';
+
+  @override
+  String get autoEqDisableOption => 'Désactiver';
 }

lib/l10n/gen/app_localizations_hi.dart

@@ -1763,4 +1763,7 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'हम अभी तक आपकी अलार्म सेटिंग्स जांच नहीं पाए हैं।';
+
+  @override
+  String get autoEqDisableOption => 'बंद करें';
 }

lib/l10n/gen/app_localizations_id.dart

@@ -1772,4 +1772,7 @@ class AppLocalizationsId extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'Kami belum bisa memeriksa pengaturan alarmmu.';
+
+  @override
+  String get autoEqDisableOption => 'Nonaktifkan';
 }

lib/l10n/gen/app_localizations_it.dart

@@ -1786,4 +1786,7 @@ class AppLocalizationsIt extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'Non abbiamo ancora potuto controllare le impostazioni della sveglia.';
+
+  @override
+  String get autoEqDisableOption => 'Disattiva';
 }

lib/l10n/gen/app_localizations_ja.dart

@@ -1711,4 +1711,7 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get alarmDiagnosticsUnavailableHint => 'アラームの設定をまだ確認できていません。';
+
+  @override
+  String get autoEqDisableOption => '無効化';
 }

lib/l10n/gen/app_localizations_pt.dart

@@ -1773,4 +1773,7 @@ class AppLocalizationsPt extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'Ainda não conseguimos verificar as configurações do seu alarme.';
+
+  @override
+  String get autoEqDisableOption => 'Desativar';
 }

lib/l10n/gen/app_localizations_ru.dart

@@ -1778,4 +1778,7 @@ class AppLocalizationsRu extends AppLocalizations {
   @override
   String get alarmDiagnosticsUnavailableHint =>
       'Мы пока не смогли проверить настройки вашего будильника.';
+
+  @override
+  String get autoEqDisableOption => 'Отключить';
 }

lib/l10n/gen/app_localizations_zh.dart

@@ -1699,4 +1699,7 @@ class AppLocalizationsZh extends AppLocalizations {
 
   @override
   String get alarmDiagnosticsUnavailableHint => '我们还无法检查你的闹钟设置。';
+
+  @override
+  String get autoEqDisableOption => '关闭';
 }