feat: onboarding screen

[ibrahimozkn]

This pull request introduces a new onboarding flow to the app, providing users with a multi-page introduction that explains the concept and benefits of N-of-1 studies and how StudyU works. It adds internationalized content for both English and German, updates routing to support the onboarding, and ensures users see the onboarding screen when no subject is found. Additionally, it includes minor localization improvements and dependency updates.

Onboarding flow implementation:

• Added a new OnboardingScreen with a multi-page introduction using the introduction_screen package. The onboarding covers what an N-of-1 study is, its importance, how it works, what StudyU provides, personal results, and instructions to start the journey. Each page supports both English and German, and includes SVG illustrations. Users can skip or complete onboarding, after which they are routed to the welcome screen. (app/lib/screens/app_onboarding/onboarding_screen.dart, app/pubspec.yaml, app/lib/routes.dart, app/lib/screens/app_onboarding/loading_screen.dart, [1] [2] [3] [4] [5] [6] [7]

Localization and internationalization:

• Added new onboarding-related localization keys and translations in both English and German ARB files, and updated the localization Dart classes to provide these strings. (app/lib/l10n/app_en.arb, app/lib/l10n/app_de.arb, app/lib/l10n/app_localizations.dart, app/lib/l10n/app_localizations_en.dart, app/lib/l10n/app_localizations_de.dart, [1] [2] [3] [4] [5]

Dependency management:

• Added the introduction_screen package to pubspec.yaml to enable the onboarding flow. Also registered the new onboarding image asset directory. [1] [2]

Routing and navigation:

• Updated app routing to include an /onboarding route, and changed the loading screen to redirect to onboarding (instead of the welcome screen) when no subject is found. [1] [2] [3]

Localization improvements (unrelated to onboarding):

• Improved the description for the "balanced" study schedule in both English and German in the designer app to clarify it now refers to a counterbalanced (ABBA) pattern. (designer_v2/lib/localization/app_localizations_en.dart, designer_v2/lib/localization/app_localizations_de.dart, [1] [2]

[Copilot]

Pull request overview

This PR implements a comprehensive onboarding flow to introduce new users to N-of-1 studies and the StudyU app. The implementation includes a 6-page guided introduction with SVG illustrations, full internationalization support (English and German), and seamless integration into the app's navigation flow. When no active subject is found, users are now directed to this onboarding experience before reaching the welcome screen.

Key changes:

• Added new OnboardingScreen component using the introduction_screen package with 6 informational pages
• Implemented complete localization support with 12 new translation keys in English and German
• Updated routing and navigation flow to redirect users without an active subject to onboarding first

Reviewed changes

Copilot reviewed 11 out of 18 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
app/lib/screens/app_onboarding/onboarding_screen.dart	New onboarding screen implementation with 6 pages explaining N-of-1 studies
app/lib/screens/app_onboarding/loading_screen.dart	Updated to redirect to onboarding instead of welcome when no subject found
app/lib/routes.dart	Added new /onboarding route registration
app/pubspec.yaml	Added introduction_screen dependency and registered onboarding assets
pubspec.lock	Updated with new dependencies for onboarding package and its transitive dependencies
app/lib/l10n/app_en.arb	Added 12 new English localization keys for onboarding content
app/lib/l10n/app_de.arb	Added 12 new German localization keys for onboarding content
app/lib/l10n/app_localizations.dart	Generated localization class with new onboarding getters
app/lib/l10n/app_localizations_en.dart	Generated English localization implementations
app/lib/l10n/app_localizations_de.dart	Generated German localization implementations and removed extraneous blank line
designer_v2/lib/localization/app_localizations_en.dart	Updated study schedule description to clarify ABBA pattern
designer_v2/lib/localization/app_localizations_de.dart	Updated German study schedule description to match English changes
app/assets/images/onboarding/page1.svg - page6.svg	New SVG illustrations for each onboarding page

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[github-actions]

Visit the preview URL for this PR (updated for commit ebba686):

• https://studyu-dev-app--pr792-feat-onboarding-scre-lagecw4x.web.app
• https://studyu-dev-designer--pr792-feat-onboarding-scre-75l88t9q.web.app

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