dialog: Cut the legacy-upgrade welcome dialog

Fixes zulip#1927.

When this app was installed as an upgrade from the legacy Zulip mobile
app, we showed a brief welcome dialog on first launch. That made sense
in the months after the 2025-06-17 launch. It's now 15 months on, past
the "perhaps after a year" that zulip#1927 suggested, so drop it.

Also drop `BoolGlobalSetting.upgradeWelcomeDialogShown`, which
recorded whether the dialog had already been shown; it's meaningless
without the dialog. Its name is reserved in the enum's list of former
settings, per the comment there.

The `legacyUpgradeState` column and its accessors stay, even though
nothing reads them now. The state says whether this install replaced
the legacy app, which may be a useful signal for zulip#1886; there's a
TODO on the getter to either use it or drop it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: chrisbobbe

assets/l10n/app_en.arb

@@ -19,22 +19,6 @@
   "@aboutPageOpenSourceLicenses": {
     "description": "Item title in About Zulip page to navigate to Licenses page"
   },
-  "upgradeWelcomeDialogTitle": "Welcome to the new Zulip app!",
-  "@upgradeWelcomeDialogTitle": {
-    "description": "Title for dialog shown on first upgrade from the legacy Zulip app."
-  },
-  "upgradeWelcomeDialogMessage": "You’ll find a familiar experience in a faster, sleeker package.",
-  "@upgradeWelcomeDialogMessage":  {
-    "description":  "Message text for dialog shown on first upgrade from the legacy Zulip app."
-  },
-  "upgradeWelcomeDialogLinkText":  "Check out the announcement blog post!",
-  "@upgradeWelcomeDialogLinkText":  {
-    "description":  "Text of link in dialog shown on first upgrade from the legacy Zulip app."
-  },
-  "upgradeWelcomeDialogDismiss": "Let's go",
-  "@upgradeWelcomeDialogDismiss":  {
-    "description":  "Label for button dismissing dialog shown on first upgrade from the legacy Zulip app."
-  },
   "chooseAccountPageTitle": "Choose account",
   "@chooseAccountPageTitle": {
     "description": "Title for the page to choose between Zulip accounts."

lib/generated/l10n/zulip_localizations.dart

@@ -189,30 +189,6 @@ abstract class ZulipLocalizations {
   /// **'Open-source licenses'**
   String get aboutPageOpenSourceLicenses;
 
-  /// Title for dialog shown on first upgrade from the legacy Zulip app.
-  ///
-  /// In en, this message translates to:
-  /// **'Welcome to the new Zulip app!'**
-  String get upgradeWelcomeDialogTitle;
-
-  /// Message text for dialog shown on first upgrade from the legacy Zulip app.
-  ///
-  /// In en, this message translates to:
-  /// **'You’ll find a familiar experience in a faster, sleeker package.'**
-  String get upgradeWelcomeDialogMessage;
-
-  /// Text of link in dialog shown on first upgrade from the legacy Zulip app.
-  ///
-  /// In en, this message translates to:
-  /// **'Check out the announcement blog post!'**
-  String get upgradeWelcomeDialogLinkText;
-
-  /// Label for button dismissing dialog shown on first upgrade from the legacy Zulip app.
-  ///
-  /// In en, this message translates to:
-  /// **'Let\'s go'**
-  String get upgradeWelcomeDialogDismiss;
-
   /// Title for the page to choose between Zulip accounts.
   ///
   /// In en, this message translates to:

lib/generated/l10n/zulip_localizations_ar.dart

@@ -28,20 +28,6 @@ class ZulipLocalizationsAr extends ZulipLocalizations {
   @override
   String get aboutPageOpenSourceLicenses => '10.0.151.1';
 
-  @override
-  String get upgradeWelcomeDialogTitle => 'أهلا بك في تطبيق زوليب الجديد !';
-
-  @override
-  String get upgradeWelcomeDialogMessage =>
-      'You’ll find a familiar experience in a faster, sleeker package.';
-
-  @override
-  String get upgradeWelcomeDialogLinkText =>
-      'Check out the announcement blog post!';
-
-  @override
-  String get upgradeWelcomeDialogDismiss => 'هيا بنا';
-
   @override
   String get chooseAccountPageTitle => 'اختر حساب';
 

lib/generated/l10n/zulip_localizations_de.dart

@@ -28,20 +28,6 @@ class ZulipLocalizationsDe extends ZulipLocalizations {
   @override
   String get aboutPageOpenSourceLicenses => 'Open-Source-Lizenzen';
 
-  @override
-  String get upgradeWelcomeDialogTitle => 'Willkommen in der neuen Zulip-App!';
-
-  @override
-  String get upgradeWelcomeDialogMessage =>
-      'Du wirst ein vertrautes Erlebnis in einer schnelleren, schlankeren App erleben.';
-
-  @override
-  String get upgradeWelcomeDialogLinkText =>
-      'Sieh dir den Ankündigungs-Blogpost an!';
-
-  @override
-  String get upgradeWelcomeDialogDismiss => 'Los gehts';
-
   @override
   String get chooseAccountPageTitle => 'Konto auswählen';
 

lib/generated/l10n/zulip_localizations_el.dart

@@ -28,20 +28,6 @@ class ZulipLocalizationsEl extends ZulipLocalizations {
   @override
   String get aboutPageOpenSourceLicenses => 'Open-source licenses';
 
-  @override
-  String get upgradeWelcomeDialogTitle => 'Welcome to the new Zulip app!';
-
-  @override
-  String get upgradeWelcomeDialogMessage =>
-      'You’ll find a familiar experience in a faster, sleeker package.';
-
-  @override
-  String get upgradeWelcomeDialogLinkText =>
-      'Check out the announcement blog post!';
-
-  @override
-  String get upgradeWelcomeDialogDismiss => 'Let\'s go';
-
   @override
   String get chooseAccountPageTitle => 'Choose account';
 

lib/generated/l10n/zulip_localizations_en.dart

@@ -28,20 +28,6 @@ class ZulipLocalizationsEn extends ZulipLocalizations {
   @override
   String get aboutPageOpenSourceLicenses => 'Open-source licenses';
 
-  @override
-  String get upgradeWelcomeDialogTitle => 'Welcome to the new Zulip app!';
-
-  @override
-  String get upgradeWelcomeDialogMessage =>
-      'You’ll find a familiar experience in a faster, sleeker package.';
-
-  @override
-  String get upgradeWelcomeDialogLinkText =>
-      'Check out the announcement blog post!';
-
-  @override
-  String get upgradeWelcomeDialogDismiss => 'Let\'s go';
-
   @override
   String get chooseAccountPageTitle => 'Choose account';
 
@@ -1450,9 +1436,6 @@ class ZulipLocalizationsEnGb extends ZulipLocalizationsEn {
   @override
   String get aboutPageOpenSourceLicenses => 'Open-source licences';
 
-  @override
-  String get upgradeWelcomeDialogTitle => 'Welcome to the new Zulip app!';
-
   @override
   String get topicValidationErrorMandatoryButEmpty =>
       'Topics are required in this organisation.';

lib/generated/l10n/zulip_localizations_es.dart

@@ -29,21 +29,6 @@ class ZulipLocalizationsEs extends ZulipLocalizations {
   @override
   String get aboutPageOpenSourceLicenses => 'Licencias de Código Abierto';
 
-  @override
-  String get upgradeWelcomeDialogTitle =>
-      '¡Te damos la bienvenida a la nueva app de Zulip!';
-
-  @override
-  String get upgradeWelcomeDialogMessage =>
-      'Encontrarás una experiencia familiar en un paquete más rápido y ligero.';
-
-  @override
-  String get upgradeWelcomeDialogLinkText =>
-      '¡Echa un vistazo al post de anuncio en blog!';
-
-  @override
-  String get upgradeWelcomeDialogDismiss => 'Vamos';
-
   @override
   String get chooseAccountPageTitle => 'Escoger cuenta';
 

lib/generated/l10n/zulip_localizations_et.dart

@@ -29,21 +29,6 @@ class ZulipLocalizationsEt extends ZulipLocalizations {
   String get aboutPageOpenSourceLicenses =>
       'Avatud lähtekoodiga tarkvara litsentsid';
 
-  @override
-  String get upgradeWelcomeDialogTitle =>
-      'Tere tulemast kasutama uut Zulipi rakendust!';
-
-  @override
-  String get upgradeWelcomeDialogMessage =>
-      'Tuttava kogemuse leiad kiiremast ja elegantsemast rakendusest.';
-
-  @override
-  String get upgradeWelcomeDialogLinkText =>
-      'Vaata teemakohast teavitust meie ajaveebi postitusest!';
-
-  @override
-  String get upgradeWelcomeDialogDismiss => 'Alustame';
-
   @override
   String get chooseAccountPageTitle => 'Vali kasutajakonto';
 

lib/generated/l10n/zulip_localizations_fr.dart

@@ -28,21 +28,6 @@ class ZulipLocalizationsFr extends ZulipLocalizations {
   @override
   String get aboutPageOpenSourceLicenses => 'Licences de logiciel libre';
 
-  @override
-  String get upgradeWelcomeDialogTitle =>
-      'Bienvenue dans la nouvelle application Zulip !';
-
-  @override
-  String get upgradeWelcomeDialogMessage =>
-      'Vous retrouverez une expérience familière dans un logiciel plus rapide et plus élégant.';
-
-  @override
-  String get upgradeWelcomeDialogLinkText =>
-      'Allez voir l\'article de blog de l\'annonce !';
-
-  @override
-  String get upgradeWelcomeDialogDismiss => 'Allons-y';
-
   @override
   String get chooseAccountPageTitle => 'Choisir un compte';
 

lib/generated/l10n/zulip_localizations_he.dart

@@ -28,20 +28,6 @@ class ZulipLocalizationsHe extends ZulipLocalizations {
   @override
   String get aboutPageOpenSourceLicenses => 'רישיונות קוד פתוח';
 
-  @override
-  String get upgradeWelcomeDialogTitle =>
-      'ברוכים הבאים לאפליקציית Zulip החדשה!';
-
-  @override
-  String get upgradeWelcomeDialogMessage =>
-      'תוכלו למצוא חוויה מוכרת בחבילה מהירה וחלקה יותר.';
-
-  @override
-  String get upgradeWelcomeDialogLinkText => 'עיין בפוסט בבלוג ההכרזה!';
-
-  @override
-  String get upgradeWelcomeDialogDismiss => 'בא נלך';
-
   @override
   String get chooseAccountPageTitle => 'בחר חשבון';