release: drop test-only build tag from settings footer

The '(build 4)' marker was a device build-delivery debugging aid, now
resolved. Public release shows a clean version string.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/ui/screens/settings_screen.dart

@@ -79,7 +79,7 @@ class SettingsScreen extends ConsumerWidget {
               const SizedBox(height: 24),
               Center(
                 child: Text(
-                  'Block Seasons · v1.0.0 (build 4)',
+                  'Block Seasons · v1.0.0',
                   style: TextStyle(
                     color: Colors.white.withValues(alpha: 0.4),
                     fontSize: 12,