Initial commit: Tagesbyte prototype

Flutter app that collects daily tech news from German and English RSS/Atom
feeds, with a reader view, AI article summaries and daily briefings (Claude
API or n8n webhook), paywall/sponsored filtering and ad/consent blocking.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/ui/common.dart

@@ -0,0 +1,86 @@
+import 'package:flutter/material.dart';
+import 'package:url_launcher/url_launcher.dart';
+
+/// User-facing app name. Platform launcher labels (AndroidManifest, Info.plist,
+/// web/manifest.json, windows/runner) are set separately.
+const appName = 'Tagesbyte';
+
+String timeAgo(DateTime? date) {
+  if (date == null) return '';
+  final diff = DateTime.now().difference(date.toLocal());
+  if (diff.inMinutes < 1) return 'just now';
+  if (diff.inMinutes < 60) return '${diff.inMinutes} min ago';
+  if (diff.inHours < 24) return '${diff.inHours} h ago';
+  if (diff.inDays == 1) return 'yesterday';
+  return '${diff.inDays} days ago';
+}
+
+String formatDateTime(DateTime date) {
+  final d = date.toLocal();
+  String two(int n) => n.toString().padLeft(2, '0');
+  return '${two(d.day)}.${two(d.month)}.${d.year} ${two(d.hour)}:${two(d.minute)}';
+}
+
+const weekdayNames = [
+  'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday',
+];
+
+const monthNames = [
+  'January', 'February', 'March', 'April', 'May', 'June',
+  'July', 'August', 'September', 'October', 'November', 'December',
+];
+
+bool isSameDay(DateTime a, DateTime b) =>
+    a.year == b.year && a.month == b.month && a.day == b.day;
+
+Future<void> openUrl(BuildContext context, String url) async {
+  final ok = await launchUrl(Uri.parse(url), mode: LaunchMode.externalApplication);
+  if (!ok && context.mounted) {
+    ScaffoldMessenger.of(context)
+        .showSnackBar(SnackBar(content: Text('Could not open $url')));
+  }
+}
+
+/// Centered icon + text + optional action, used for empty and error states.
+class EmptyState extends StatelessWidget {
+  const EmptyState({
+    super.key,
+    required this.icon,
+    required this.title,
+    this.message,
+    this.action,
+  });
+
+  final IconData icon;
+  final String title;
+  final String? message;
+  final Widget? action;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    return Center(
+      child: Padding(
+        padding: const EdgeInsets.all(32),
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            Icon(icon, size: 56, color: theme.colorScheme.primary),
+            const SizedBox(height: 16),
+            Text(title, style: theme.textTheme.titleMedium, textAlign: TextAlign.center),
+            if (message != null) ...[
+              const SizedBox(height: 8),
+              Text(
+                message!,
+                style: theme.textTheme.bodyMedium
+                    ?.copyWith(color: theme.colorScheme.onSurfaceVariant),
+                textAlign: TextAlign.center,
+              ),
+            ],
+            if (action != null) ...[const SizedBox(height: 20), action!],
+          ],
+        ),
+      ),
+    );
+  }
+}