perf(startup): paint a splash immediately, run init off the first frame

main() awaited all of configureDependencies() (open the encrypted DB,
derive the social key, seed/scan the species catalog) before the first
runApp, so nothing painted until init finished — startup jank visible as
skipped frames. Now main() runs runApp immediately with a Bootstrap
widget that shows a native-splash-matching green splash while the heavy
work runs, then swaps in TaneApp. On failure it shows a localized error
with a retry (configureDependencies is idempotent, so retry is safe).

Adds a bootstrap i18n group (en/es/pt/ast) and a widget test for the
splash/error frame.

apps/app_seeds/lib/bootstrap.dart

@@ -0,0 +1,162 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
+
+import 'app.dart';
+import 'data/species_repository.dart';
+import 'data/variety_repository.dart';
+import 'di/injector.dart';
+import 'i18n/strings.g.dart';
+import 'services/auto_backup_service.dart';
+import 'services/coarse_location.dart';
+import 'services/inbox_service.dart';
+import 'services/locale_store.dart';
+import 'services/message_store.dart';
+import 'services/offer_outbox.dart';
+import 'services/onboarding_store.dart';
+import 'services/profile_cache.dart';
+import 'services/profile_store.dart';
+import 'services/social_service.dart';
+import 'services/social_settings.dart';
+import 'ui/theme.dart';
+
+/// Boots the app WITHOUT blocking the first frame: paints a splash immediately,
+/// then wires the encrypted DB + services and swaps in [TaneApp] once ready.
+///
+/// Before this, `main` awaited the whole of `configureDependencies()` (open the
+/// encrypted DB, derive the social key, seed/scan the species catalog…) before
+/// the first `runApp`, so nothing painted until init finished — the startup jank
+/// visible as skipped frames. Now `main` runs `runApp` immediately with this
+/// widget; the heavy work runs while the splash is already on screen.
+class Bootstrap extends StatefulWidget {
+  const Bootstrap({super.key});
+
+  @override
+  State<Bootstrap> createState() => _BootstrapState();
+}
+
+class _BootstrapState extends State<Bootstrap> {
+  late Future<TaneApp> _app = _boot();
+
+  Future<TaneApp> _boot() async {
+    await configureDependencies();
+
+    // The saved language lives in the keystore, so it can only be applied once
+    // DI is up. Until now the splash showed in the device language (it has no
+    // text), so there is no visible flip.
+    final savedLocale = await getIt<LocaleStore>().saved();
+    if (savedLocale != null) LocaleSettings.setLocaleSync(savedLocale);
+
+    final onboarding = getIt<OnboardingStore>();
+    final inbox =
+        getIt.isRegistered<InboxService>() ? getIt<InboxService>() : null;
+    // Listen for incoming private messages app-wide (foreground) so they arrive
+    // and fill the inbox even before their chat is opened.
+    if (inbox != null) unawaited(inbox.start());
+
+    return TaneApp(
+      repository: getIt<VarietyRepository>(),
+      species: getIt<SpeciesRepository>(),
+      onboarding: onboarding,
+      social:
+          getIt.isRegistered<SocialService>() ? getIt<SocialService>() : null,
+      socialSettings: getIt<SocialSettings>(),
+      location: const GeolocatorCoarseLocation(),
+      outbox: getIt<OfferOutbox>(),
+      messageStore: getIt<MessageStore>(),
+      profileStore: getIt<ProfileStore>(),
+      profileCache: getIt<ProfileCache>(),
+      inbox: inbox,
+      showIntro: !await onboarding.introSeen(),
+      autoBackup: getIt.isRegistered<AutoBackupService>()
+          ? getIt<AutoBackupService>()
+          : null,
+    );
+  }
+
+  // `configureDependencies` is idempotent (and self-heals a half-wired
+  // container), so retrying after a failed boot is safe.
+  void _retry() => setState(() => _app = _boot());
+
+  @override
+  Widget build(BuildContext context) {
+    return FutureBuilder<TaneApp>(
+      future: _app,
+      builder: (context, snapshot) {
+        if (snapshot.hasData) return snapshot.data!;
+        return BootstrapSplash(
+          error: snapshot.hasError,
+          onRetry: snapshot.hasError ? _retry : null,
+        );
+      },
+    );
+  }
+}
+
+/// The pre-init frame. A minimal [MaterialApp] so its text has a
+/// `Directionality`, theme and localizations. Its background matches the native
+/// splash colour ([seedGreen]) for a seamless handoff — one continuous green
+/// screen from launch until the app is ready. Shows a spinner while booting and,
+/// on [error], the failure message with a [onRetry] action.
+class BootstrapSplash extends StatelessWidget {
+  const BootstrapSplash({required this.error, this.onRetry, super.key});
+
+  final bool error;
+  final VoidCallback? onRetry;
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      debugShowCheckedModeBanner: false,
+      theme: buildTaneTheme(),
+      locale: TranslationProvider.of(context).flutterLocale,
+      supportedLocales: AppLocaleUtils.supportedLocales,
+      localizationsDelegates: const [
+        GlobalMaterialLocalizations.delegate,
+        GlobalWidgetsLocalizations.delegate,
+        GlobalCupertinoLocalizations.delegate,
+      ],
+      home: Scaffold(
+        backgroundColor: seedGreen,
+        body: Center(
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              Image.asset('assets/logo.png', width: 120, height: 120),
+              const SizedBox(height: 32),
+              if (error) ...[
+                Padding(
+                  padding: const EdgeInsets.symmetric(horizontal: 32),
+                  child: Text(
+                    context.t.bootstrap.failed,
+                    textAlign: TextAlign.center,
+                    style: const TextStyle(color: Colors.white, fontSize: 16),
+                  ),
+                ),
+                const SizedBox(height: 16),
+                if (onRetry != null)
+                  FilledButton(
+                    onPressed: onRetry,
+                    style: FilledButton.styleFrom(
+                      backgroundColor: Colors.white,
+                      foregroundColor: seedGreen,
+                    ),
+                    child: Text(context.t.bootstrap.retry),
+                  ),
+              ] else
+                const SizedBox(
+                  width: 28,
+                  height: 28,
+                  child: CircularProgressIndicator(
+                    strokeWidth: 3,
+                    valueColor: AlwaysStoppedAnimation(Colors.white),
+                  ),
+                ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}