feat(about): add Comunes Association copyleft notice à la Ğ1nkgo

apps/app_seeds/lib/ui/about_screen.dart

@@ -8,6 +8,19 @@ import 'theme.dart';
 /// The app's public website. Shown as a tappable row in [AboutScreen].
 const String _websiteUrl = 'https://tanemaki.app';
 
+/// The year Tanemaki's copyright starts. Ğ1nkgo uses its own first year (2023);
+/// Tanemaki's is 2026.
+const int _copyrightStartYear = 2026;
+
+/// A single year (`2026`) until the calendar rolls over, then a range
+/// (`2026-2027`), mirroring Ğ1nkgo's legalese line.
+String _copyrightYears() {
+  final int now = DateTime.now().year;
+  return now <= _copyrightStartYear
+      ? '$_copyrightStartYear'
+      : '$_copyrightStartYear-$now';
+}
+
 /// An "about" screen à la Ğ1nkgo: brand header, the human explanation of what
 /// Tanemaki is and where its name comes from, the app version, license, the
 /// website, and the bundled open-source licenses page.
@@ -62,12 +75,24 @@ class AboutScreen extends StatelessWidget {
             onTap: () => showLicensePage(
               context: context,
               applicationName: t.app.title,
+              applicationLegalese: t.about.copyright(years: _copyrightYears()),
               applicationIcon: Padding(
                 padding: const EdgeInsets.all(8),
                 child: Image.asset('assets/logo.png', width: 48),
               ),
             ),
           ),
+          const Divider(height: 32),
+          Padding(
+            padding: const EdgeInsets.symmetric(horizontal: 20),
+            child: Text(
+              t.about.copyright(years: _copyrightYears()),
+              textAlign: TextAlign.center,
+              style: Theme.of(context).textTheme.bodySmall?.copyWith(
+                color: seedOnSurface.withValues(alpha: 0.7),
+              ),
+            ),
+          ),
         ],
       ),
     );