feat(observability): add Firebase Crashlytics with opt-in toggle in settings

[using-system]

Summary

• Integrate Firebase Crashlytics SDK (firebase_core, firebase_crashlytics) with Android Gradle plugin configuration
• Add new Observability settings section (between General and Actions) with a crash reporting on/off toggle (default: off)
• Firebase initialization wrapped in try-catch so the app runs normally on platforms without Firebase config (iOS)
• Full i18n support across all 4 locales (en, fr, de, es)
• 11 unit/widget tests covering storage, toggle tile, and section

Test plan

• Verify toggle defaults to off on fresh install
• Toggle on → check setCrashlyticsCollectionEnabled(true) called
• Toggle off → persists across app restart
• Force a crash with toggle on → verify crash appears in Firebase Console
• Run on iOS without GoogleService-Info.plist → app launches normally, toggle has no effect
• flutter test test/features/observability/ → 11 tests pass
• flutter analyze → no new issues

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds opt-in Firebase Crashlytics integration to the app, exposing a new “Observability” settings section with a crash reporting toggle and persisting the preference via SharedPreferences.

Changes:

• Add Firebase Crashlytics + Firebase Core dependencies and Android Gradle plugin wiring.
• Add an Observability settings section with a Crashlytics on/off toggle backed by Riverpod + SharedPreferences.
• Add i18n strings and unit/widget tests for the new storage and UI.

Reviewed changes

Copilot reviewed 20 out of 21 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
pubspec.yaml	Adds firebase_core and firebase_crashlytics dependencies.
pubspec.lock	Locks Firebase/Crashlytics transitive dependencies.
lib/main.dart	Initializes Firebase/Crashlytics at startup and conditionally wraps runApp in a guarded zone.
lib/features/settings/presentation/settings_page.dart	Inserts the Observability section between General and Actions.
lib/features/observability/data/crashlytics_preference_storage.dart	Implements SharedPreferences read/write for the Crashlytics opt-in boolean.
lib/features/observability/providers.dart	Adds Riverpod providers/notifier to read/write preference and call Crashlytics SDK.
lib/features/observability/presentation/crashlytics_toggle_tile.dart	Adds the SwitchListTile UI + error snackbar on write failures.
lib/features/observability/presentation/observability_section.dart	Groups observability settings tiles for the Settings page.
lib/l10n/app_en.arb	Adds EN strings (and metadata) for Observability + Crashlytics toggle.
lib/l10n/app_fr.arb	Adds FR strings for Observability + Crashlytics toggle.
lib/l10n/app_de.arb	Adds DE strings for Observability + Crashlytics toggle.
lib/l10n/app_es.arb	Adds ES strings for Observability + Crashlytics toggle.
android/settings.gradle.kts	Adds Google Services + Crashlytics Gradle plugins (pluginManagement).
android/app/build.gradle.kts	Applies Google Services + Crashlytics plugins to the Android app module.
android/app/google-services.json	Adds Firebase Android config (currently committed).
SPEC.md	Documents Crashlytics in the tech stack under Observability.
docs/superpowers/specs/2026-04-21-firebase-crashlytics-design.md	Design doc for Crashlytics integration and toggle behavior.
docs/superpowers/plans/2026-04-21-firebase-crashlytics.md	Step-by-step implementation plan for the feature.
test/features/observability/data/crashlytics_preference_storage_test.dart	Tests for storage default/overwrite/corruption handling.
test/features/observability/presentation/crashlytics_toggle_tile_test.dart	Widget tests for toggle UI and persistence.
test/features/observability/presentation/observability_section_test.dart	Widget tests ensuring section contains tile and divider.

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[Copilot]

Pull request overview

Copilot reviewed 20 out of 21 changed files in this pull request and generated 3 comments.

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[Copilot]

The zone error handler calls FirebaseCrashlytics.instance.recordError(...) unconditionally. If Firebase initialization was skipped/failed in the try block (e.g., missing config on iOS), this will likely throw ("no default Firebase app") and can cascade into additional unhandled errors. Guard this call behind a Firebase-initialized check (e.g., Firebase.apps.isNotEmpty) and/or wrap it in a try/catch with a fallback logger so the app remains stable when Firebase is unavailable.

Suggested change

	(error, stack) {
	FirebaseCrashlytics.instance.recordError(error, stack, fatal: true);
	(error, stack) async {
	if (Firebase.apps.isEmpty) {
	debugPrint('Unhandled zone error (Firebase unavailable): $error\n$stack');
	return;
	}
	try {
	await FirebaseCrashlytics.instance
	.recordError(error, stack, fatal: true);
	} catch (e, crashlyticsStack) {
	debugPrint(
	'Failed to report error to Crashlytics: $e\n$crashlyticsStack\n'
	'Original error: $error\n$stack',
	);
	}

[Copilot]

This spec’s module file map no longer matches the implemented code: it references observability_storage.dart and a domain/ preference type, but the PR introduces data/crashlytics_preference_storage.dart (and no domain/ layer). Please update the file map to reflect the actual paths/structure so future contributors don’t follow stale guidance.

[Copilot]

This plan states Firebase config files are gitignored and must be placed manually, but the PR also adds android/app/google-services.json to version control. Either update the plan to match the new approach, or (preferably) keep the config files out of the repo by gitignoring them and removing committed copies.