fix(inventory): recover from a stuck loading spinner

The inventory stream subscription had no onError handler, so a transient
failure at startup (e.g. the encrypted DB not yet ready) went unhandled
and left loading=true forever — the spinner that only a restart cleared.

Handle stream errors: drop out of loading, surface an error state, and
offer a retry that re-opens the stream. Add a _LoadError view (i18n en/
es/ast/pt) and cover both the failure and the retry-recovers paths.

apps/app_seeds/lib/ui/inventory_list_screen.dart

@@ -46,7 +46,9 @@ class InventoryListScreen extends StatelessWidget {
                   ),
                   child: const Icon(Icons.add),
                 ),
-          body: state.loading
+          body: state.error != null
+              ? _LoadError(onRetry: context.read<InventoryCubit>().retry)
+              : state.loading
               ? const Center(child: CircularProgressIndicator())
               : Column(
                   children: [
@@ -237,6 +239,38 @@ class InventoryListScreen extends StatelessWidget {
 
 /// A tappable banner announcing how many photo-first captures are waiting to be
 /// named. Opens the "to catalogue" tray.
+/// Shown when the inventory stream fails to open — instead of an endless
+/// spinner, offer a clear message and a way to try again.
+class _LoadError extends StatelessWidget {
+  const _LoadError({required this.onRetry});
+
+  final VoidCallback onRetry;
+
+  @override
+  Widget build(BuildContext context) {
+    final t = context.t;
+    return Center(
+      child: Padding(
+        padding: const EdgeInsets.all(24),
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            const Icon(Icons.cloud_off_outlined, size: 48, color: seedGreen),
+            const SizedBox(height: 16),
+            Text(t.inventory.loadError, textAlign: TextAlign.center),
+            const SizedBox(height: 16),
+            FilledButton(
+              key: const Key('inventory.retry'),
+              onPressed: onRetry,
+              child: Text(t.inventory.retry),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}
+
 class _TriageBanner extends StatelessWidget {
   const _TriageBanner({required this.count});