Make Analytics injectable for testability

[Copilot]

Analytics(getBackend()) calls FirebaseAnalytics.instance directly, preventing widget tests from mocking analytics. The root Sharezone widget cannot be tested as a result.

Changes

Core widget refactoring

• Sharezone accepts optional Analytics parameter, falls back to blocDependencies.analytics
• Removed static Analytics field in favor of instance parameter
• Centralized Analytics creation in run_app.dart (single instance, passed to both RegistrationGateway and BlocDependencies)

Gateway updates

• RegistrationGateway and LinkProviderGateway accept optional Analytics parameter
• All default to Analytics(getBackend()) when not provided (backward compatible)

BLoC and page integration

• AccountPageBlocFactory, EmailAndPasswordLinkBloc accept optional Analytics
• AuthApp provides Analytics via Provider for login/signup flows
• Pages use context.read<Analytics>() or BlocProvider.of<SharezoneContext>(context).analytics

Example

// Tests can now mock Analytics
final mockAnalytics = Analytics(NullAnalyticsBackend());
final sharezone = Sharezone(
  blocDependencies: deps,
  analytics: mockAnalytics,  // Injectable
  // ...
);

// Production code unchanged (defaults work)
final sharezone = Sharezone(
  blocDependencies: deps,  // Uses deps.analytics
  // ...
);

All existing code works unchanged. Tests can now pass NullAnalyticsBackend for mocking.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Refactor the usage of Analytics(getBackend())</issue_title>
<issue_description>In many places of this app we use Analytics(getBackend(). This is a problem because we can't run our root widget Sharezone in a widget test. getBackend() calls FirebaseAnalytics.instance which is not mockable. Instead, should pass a FirebaseAnalytics object so that we can pass a mocked version in tests.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Refactor the usage of Analytics(getBackend()) #1379

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.