feat(block2): global 'you're offline' banner (network state)

Feedback: offline, the social layer stops working with no clear reason. A slim
amber strip now shows above every screen when there's no network (connectivity_
plus), so it's obvious WHY sharing is paused — the inventory keeps working.
Wrapped once via the MaterialApp builder; connectivity check is guarded so it
no-ops where the plugin is absent (tests/unsupported platforms). i18n en/es/pt.
Analyzer clean.

apps/app_seeds/lib/app.dart

@@ -26,6 +26,7 @@ import 'ui/home_screen.dart';
 import 'ui/intro_screen.dart';
 import 'ui/inventory_list_screen.dart';
 import 'ui/market_screen.dart';
+import 'ui/offline_banner.dart';
 import 'ui/profile_screen.dart';
 import 'ui/settings_screen.dart';
 import 'ui/theme.dart';
@@ -212,6 +213,10 @@ class TaneApp extends StatelessWidget {
             GlobalWidgetsLocalizations.delegate,
             GlobalCupertinoLocalizations.delegate,
           ],
+          // A global "you're offline" strip above every screen — makes it clear
+          // why the social layer is paused (the inventory still works).
+          builder: (context, child) =>
+              OfflineBanner(child: child ?? const SizedBox.shrink()),
           routerConfig: _router,
         ),
       ),

apps/app_seeds/lib/i18n/en.i18n.json

@@ -8,7 +8,8 @@
     "delete": "Delete",
     "edit": "Edit",
     "type": "Type",
-    "comingSoon": "Coming soon"
+    "comingSoon": "Coming soon",
+    "offline": "You're offline — sharing is paused"
   },
   "home": {
     "tagline": "Share and grow local seeds",

apps/app_seeds/lib/i18n/es.i18n.json

@@ -8,7 +8,8 @@
     "delete": "Eliminar",
     "edit": "Editar",
     "type": "Tipo",
-    "comingSoon": "Pronto"
+    "comingSoon": "Pronto",
+    "offline": "Sin conexión — el compartir está en pausa"
   },
   "home": {
     "tagline": "Comparte y cultiva semillas locales",

apps/app_seeds/lib/i18n/pt.i18n.json

@@ -8,7 +8,8 @@
     "delete": "Eliminar",
     "edit": "Editar",
     "type": "Tipo",
-    "comingSoon": "Em breve"
+    "comingSoon": "Em breve",
+    "offline": "Sem ligação — a partilha está em pausa"
   },
   "home": {
     "tagline": "Partilha e cultiva sementes locais",

apps/app_seeds/lib/i18n/strings.g.dart

@@ -4,9 +4,9 @@
 /// To regenerate, run: `dart run slang`
 ///
 /// Locales: 3
-/// Strings: 1073 (357 per locale)
+/// Strings: 1076 (358 per locale)
 ///
-/// Built on 2026-07-10 at 11:35 UTC
+/// Built on 2026-07-10 at 13:17 UTC
 
 // coverage:ignore-file
 // ignore_for_file: type=lint, unused_import

apps/app_seeds/lib/i18n/strings_en.g.dart

@@ -113,6 +113,9 @@ class Translations$common$en {
 
 	/// en: 'Coming soon'
 	String get comingSoon => 'Coming soon';
+
+	/// en: 'You're offline — sharing is paused'
+	String get offline => 'You\'re offline — sharing is paused';
 }
 
 // Path: home
@@ -1755,6 +1758,7 @@ extension on Translations {
 			'common.edit' => 'Edit',
 			'common.type' => 'Type',
 			'common.comingSoon' => 'Coming soon',
+			'common.offline' => 'You\'re offline — sharing is paused',
 			'home.tagline' => 'Share and grow local seeds',
 			'home.openMarket' => 'Market',
 			'home.openMarketSubtitle' => 'Discover and share seeds nearby',

apps/app_seeds/lib/i18n/strings_es.g.dart

@@ -98,6 +98,7 @@ class _Translations$common$es extends Translations$common$en {
 	@override String get edit => 'Editar';
 	@override String get type => 'Tipo';
 	@override String get comingSoon => 'Pronto';
+	@override String get offline => 'Sin conexión — el compartir está en pausa';
 }
 
 // Path: home
@@ -1057,6 +1058,7 @@ extension on TranslationsEs {
 			'common.edit' => 'Editar',
 			'common.type' => 'Tipo',
 			'common.comingSoon' => 'Pronto',
+			'common.offline' => 'Sin conexión — el compartir está en pausa',
 			'home.tagline' => 'Comparte y cultiva semillas locales',
 			'home.openMarket' => 'Mercado',
 			'home.openMarketSubtitle' => 'Descubre y comparte semillas cerca',

apps/app_seeds/lib/i18n/strings_pt.g.dart

@@ -98,6 +98,7 @@ class _Translations$common$pt extends Translations$common$en {
 	@override String get edit => 'Editar';
 	@override String get type => 'Tipo';
 	@override String get comingSoon => 'Em breve';
+	@override String get offline => 'Sem ligação — a partilha está em pausa';
 }
 
 // Path: home
@@ -1053,6 +1054,7 @@ extension on TranslationsPt {
 			'common.edit' => 'Editar',
 			'common.type' => 'Tipo',
 			'common.comingSoon' => 'Em breve',
+			'common.offline' => 'Sem ligação — a partilha está em pausa',
 			'home.tagline' => 'Partilha e cultiva sementes locais',
 			'home.openMarket' => 'Mercado',
 			'home.openMarketSubtitle' => 'Descobre e partilha sementes por perto',

apps/app_seeds/lib/ui/offline_banner.dart

@@ -0,0 +1,87 @@
+import 'dart:async';
+
+import 'package:connectivity_plus/connectivity_plus.dart';
+import 'package:flutter/material.dart';
+
+import '../i18n/strings.g.dart';
+
+/// Wraps the app and shows a slim strip at the very top when there's no network,
+/// so it's clear WHY the social layer (market, chat, profile) is paused — the
+/// inventory keeps working offline. Wrap the whole app once (MaterialApp builder).
+class OfflineBanner extends StatefulWidget {
+  const OfflineBanner({required this.child, super.key});
+
+  final Widget child;
+
+  @override
+  State<OfflineBanner> createState() => _OfflineBannerState();
+}
+
+class _OfflineBannerState extends State<OfflineBanner> {
+  bool _offline = false;
+  StreamSubscription<List<ConnectivityResult>>? _sub;
+
+  @override
+  void initState() {
+    super.initState();
+    _init();
+  }
+
+  Future<void> _init() async {
+    try {
+      final current = await Connectivity().checkConnectivity();
+      if (mounted) setState(() => _offline = _isOffline(current));
+      _sub = Connectivity().onConnectivityChanged.listen((results) {
+        if (mounted) setState(() => _offline = _isOffline(results));
+      });
+    } catch (_) {
+      // Platform without connectivity support → assume online, hide the banner.
+    }
+  }
+
+  bool _isOffline(List<ConnectivityResult> results) =>
+      results.isEmpty ||
+      results.every((r) => r == ConnectivityResult.none);
+
+  @override
+  void dispose() {
+    _sub?.cancel();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      children: [
+        if (_offline)
+          Material(
+            color: const Color(0xFFE8A200), // amber — not an error, just paused
+            child: SafeArea(
+              bottom: false,
+              child: Padding(
+                padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 6),
+                child: Row(
+                  mainAxisAlignment: MainAxisAlignment.center,
+                  children: [
+                    const Icon(Icons.cloud_off, size: 16, color: Colors.white),
+                    const SizedBox(width: 8),
+                    Flexible(
+                      child: Text(
+                        context.t.common.offline,
+                        style: const TextStyle(
+                          color: Colors.white,
+                          fontSize: 12.5,
+                          fontWeight: FontWeight.w500,
+                        ),
+                      ),
+                    ),
+                  ],
+                ),
+              ),
+            ),
+          ),
+        Expanded(child: widget.child),
+      ],
+    );
+  }
+}

apps/app_seeds/pubspec.yaml

@@ -71,6 +71,9 @@ dependencies:
   # typing a code. Low accuracy only; the value is immediately reduced to a
   # low-precision geohash. Behind an interface so it's fakeable and pluggable.
   geolocator: ^13.0.1
+  # Network reachability (BSD-3) to show a global "you're offline" banner — the
+  # social layer needs a connection; the inventory works regardless.
+  connectivity_plus: ^6.1.0
 
 dev_dependencies:
   flutter_test: