Scalar Presence: brand-panel login (light/dark), Poppins, splash and launcher icons, fixed API base via dart-define, keep-signed-in, Android project

- Login reworked to the Brand panel layout with a dark-theme switch; 'Scalar Presence' two-line wordmark
- Android project now tracked (was gitignored); pins shared_preferences_android 2.4.27 (2.5.0 crashed with a black screen)
- API base URL fixed per build (--dart-define=API_BASE_URL), no in-app server setting

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

lib/screens/settings_screen.dart

@@ -12,14 +12,6 @@ class SettingsScreen extends StatefulWidget {
 }
 
 class _SettingsScreenState extends State<SettingsScreen> {
-  late final TextEditingController _url = TextEditingController(text: widget.settings.baseUrl);
-
-  void _save() {
-    widget.settings.baseUrl = _url.text.trim();
-    ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('Saved')));
-    setState(() {});
-  }
-
   @override
   Widget build(BuildContext context) {
     final name = widget.settings.name;
@@ -36,22 +28,8 @@ class _SettingsScreenState extends State<SettingsScreen> {
                 subtitle: Text(widget.settings.isManager ? 'Manager' : 'Employee'),
               ),
             ),
-          const SizedBox(height: 20),
-          const Text('Server URL', style: TextStyle(fontWeight: FontWeight.w600, color: AppColors.navy)),
-          const SizedBox(height: 8),
-          TextField(
-            controller: _url,
-            keyboardType: TextInputType.url,
-            autocorrect: false,
-            decoration: const InputDecoration(prefixIcon: Icon(Icons.link), hintText: Settings.defaultBaseUrl),
-          ),
-          const SizedBox(height: 6),
-          const Text('The Scalar360 API base URL. Default is api.scalar360.in.',
-              style: TextStyle(fontSize: 12, color: AppColors.muted)),
-          const SizedBox(height: 16),
-          FilledButton(onPressed: _save, child: const Text('Save')),
           if (widget.onLogout != null) ...[
-            const SizedBox(height: 32),
+            const SizedBox(height: 20),
             OutlinedButton.icon(
               onPressed: widget.onLogout,
               icon: const Icon(Icons.logout, color: AppColors.danger),