feat: Add theme customization options in settings screen and update app theme logic

lib/screens/settings_screen.dart

@@ -9,11 +9,15 @@ class SettingsScreen extends StatefulWidget {
     required this.onDeleteAllData,
     required this.onBackToHome,
     required this.onForceSync,
+    required this.currentSeedColor,
+    required this.onThemeColorSelected,
   });
 
   final Future<void> Function() onDeleteAllData;
   final VoidCallback onBackToHome;
   final Future<void> Function() onForceSync;
+  final Color currentSeedColor;
+  final Future<void> Function(Color color) onThemeColorSelected;
 
   @override
   State<SettingsScreen> createState() => _SettingsScreenState();
@@ -22,11 +26,22 @@ class SettingsScreen extends StatefulWidget {
 class _SettingsScreenState extends State<SettingsScreen> {
   bool _isBusy = false;
   bool _isSyncing = false;
+  bool _isThemeSaving = false;
   final TextEditingController _endpointController = TextEditingController();
   final TextEditingController _encryptionKeyController = TextEditingController();
   bool _endpointLoading = true;
   bool _encryptionKeyLoading = false;
   bool _encryptionKeyVisible = false;
+  late Color _selectedSeedColor;
+
+  static const List<Color> _themeColorOptions = <Color>[
+    Colors.amber,
+    Colors.blue,
+    Colors.teal,
+    Colors.green,
+    Colors.pink,
+    Colors.purple,
+  ];
 
   Future<void> _confirmAndDeleteAll() async {
     final bool? confirmed = await showDialog<bool>(
@@ -100,12 +115,56 @@ class _SettingsScreenState extends State<SettingsScreen> {
     }
   }
 
+  Future<void> _selectThemeColor(Color color) async {
+    if (_isThemeSaving || _selectedSeedColor == color) {
+      return;
+    }
+
+    final Color previousColor = _selectedSeedColor;
+    setState(() {
+      _selectedSeedColor = color;
+      _isThemeSaving = true;
+    });
+
+    try {
+      await widget.onThemeColorSelected(color);
+    } catch (error) {
+      if (!mounted) {
+        return;
+      }
+
+      setState(() {
+        _selectedSeedColor = previousColor;
+      });
+
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text('No se pudo guardar el color: $error')),
+      );
+    } finally {
+      if (mounted) {
+        setState(() {
+          _isThemeSaving = false;
+        });
+      }
+    }
+  }
+
   @override
   void initState() {
     super.initState();
+    _selectedSeedColor = widget.currentSeedColor;
     _loadEndpoint();
   }
 
+  @override
+  void didUpdateWidget(covariant SettingsScreen oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.currentSeedColor != widget.currentSeedColor &&
+        widget.currentSeedColor != _selectedSeedColor) {
+      _selectedSeedColor = widget.currentSeedColor;
+    }
+  }
+
   Future<void> _loadEndpoint() async {
     final String endpoint = await ApiConfig.getEndpoint();
     if (!mounted) return;
@@ -160,6 +219,58 @@ class _SettingsScreenState extends State<SettingsScreen> {
     });
   }
 
+  Widget _buildThemeColorButton(Color color) {
+    final bool isSelected = _selectedSeedColor.value == color.value;
+    final Color foregroundColor =
+        ThemeData.estimateBrightnessForColor(color) == Brightness.dark
+            ? Colors.white
+            : Colors.black;
+
+    return Semantics(
+      button: true,
+      selected: isSelected,
+      label: 'Color ${color.value.toRadixString(16)}',
+      child: Tooltip(
+        message: isSelected ? 'Color actual' : 'Usar este color',
+        child: InkWell(
+          onTap: _isThemeSaving ? null : () => _selectThemeColor(color),
+          borderRadius: BorderRadius.circular(12),
+          child: AnimatedContainer(
+            duration: const Duration(milliseconds: 180),
+            width: 44,
+            height: 44,
+            decoration: BoxDecoration(
+              color: color,
+              borderRadius: BorderRadius.circular(12),
+              border: Border.all(
+                color: isSelected ? Colors.white : Colors.white24,
+                width: isSelected ? 2.5 : 1.2,
+              ),
+              boxShadow: [
+                BoxShadow(
+                  color: Colors.black.withValues(alpha: 0.25),
+                  blurRadius: 8,
+                  offset: const Offset(0, 3),
+                ),
+              ],
+            ),
+            child: Stack(
+              alignment: Alignment.center,
+              children: [
+                if (isSelected)
+                  Icon(
+                    Icons.check,
+                    size: 22,
+                    color: foregroundColor,
+                  ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+
   @override
   void dispose() {
     _endpointController.dispose();
@@ -296,11 +407,6 @@ class _SettingsScreenState extends State<SettingsScreen> {
                             child: Text('Forzar sincronizacion total:'),
                           ),
                           ElevatedButton.icon(
-                            style: ElevatedButton.styleFrom(
-                              backgroundColor: Colors.amber,
-                              foregroundColor: Colors.black,
-                              textStyle: const TextStyle(fontWeight: FontWeight.w700),
-                            ),
                             onPressed: (_isBusy || _isSyncing) ? null : _forceSync,
                             icon: _isSyncing
                                 ? const SizedBox(
@@ -314,6 +420,17 @@ class _SettingsScreenState extends State<SettingsScreen> {
                         ],
                       ),
                       const SizedBox(height: 24),
+                      const Text('Color del esquema'),
+                      const SizedBox(height: 8),
+                      Wrap(
+                        spacing: 12,
+                        runSpacing: 12,
+                        children: [
+                          for (final Color color in _themeColorOptions)
+                            _buildThemeColorButton(color),
+                        ],
+                      ),
+                      const SizedBox(height: 24),
                       const Text('API endpoint (ej: http://localhost:3000/api)'),
                       const SizedBox(height: 8),
                       _buildResponsiveInputActionsRow(