feat(mobile): Implement Keycloak WebView authentication with HTTP callback

- Replace flutter_appauth with custom WebView implementation to resolve deep link issues
- Add KeycloakWebViewAuthService with integrated WebView for seamless authentication
- Configure Android manifest for HTTP cleartext traffic support
- Add network security config for development environment (192.168.1.11)
- Update Keycloak client to use HTTP callback endpoint (http://192.168.1.11:8080/auth/callback)
- Remove obsolete keycloak_auth_service.dart and temporary scripts
- Clean up dependencies and regenerate injection configuration
- Tested successfully on multiple Android devices (Xiaomi 2201116TG, SM A725F)

BREAKING CHANGE: Authentication flow now uses WebView instead of external browser
- Users will see Keycloak login page within the app instead of browser redirect
- Resolves ERR_CLEARTEXT_NOT_PERMITTED and deep link state management issues
- Maintains full OIDC compliance with PKCE flow and secure token storage

Technical improvements:
- WebView with custom navigation delegate for callback handling
- Automatic token extraction and user info parsing from JWT
- Proper error handling and user feedback
- Consistent authentication state management across app lifecycle

unionflow-mobile-apps/lib/features/members/presentation/widgets/professional_pie_chart.dart

@@ -65,7 +65,7 @@ class _ProfessionalPieChartState extends State<ProfessionalPieChart>
       crossAxisAlignment: CrossAxisAlignment.start,
       children: [
         _buildHeader(),
-        SizedBox(height: DesignSystem.spacingLg),
+        const SizedBox(height: DesignSystem.spacingLg),
         Expanded(
           child: Row(
             children: [
@@ -74,7 +74,7 @@ class _ProfessionalPieChartState extends State<ProfessionalPieChart>
                 child: _buildChart(),
               ),
               if (widget.showLegend) ...[
-                SizedBox(width: DesignSystem.spacingLg),
+                const SizedBox(width: DesignSystem.spacingLg),
                 Expanded(
                   flex: 2,
                   child: _buildLegend(),
@@ -98,7 +98,7 @@ class _ProfessionalPieChartState extends State<ProfessionalPieChart>
           ),
         ),
         if (widget.subtitle != null) ...[
-          SizedBox(height: DesignSystem.spacingXs),
+          const SizedBox(height: DesignSystem.spacingXs),
           Text(
             widget.subtitle!,
             style: DesignSystem.bodyMedium.copyWith(
@@ -177,7 +177,7 @@ class _ProfessionalPieChartState extends State<ProfessionalPieChart>
 
   Widget _buildBadge(ChartDataPoint data) {
     return Container(
-      padding: EdgeInsets.symmetric(
+      padding: const EdgeInsets.symmetric(
         horizontal: DesignSystem.spacingSm,
         vertical: DesignSystem.spacingXs,
       ),
@@ -203,7 +203,7 @@ class _ProfessionalPieChartState extends State<ProfessionalPieChart>
       children: [
         if (widget.centerText != null) ...[
           _buildCenterInfo(),
-          SizedBox(height: DesignSystem.spacingLg),
+          const SizedBox(height: DesignSystem.spacingLg),
         ],
         ...widget.data.asMap().entries.map((entry) {
           final index = entry.key;
@@ -212,8 +212,8 @@ class _ProfessionalPieChartState extends State<ProfessionalPieChart>
           
           return AnimatedContainer(
             duration: DesignSystem.animationFast,
-            margin: EdgeInsets.only(bottom: DesignSystem.spacingSm),
-            padding: EdgeInsets.all(DesignSystem.spacingSm),
+            margin: const EdgeInsets.only(bottom: DesignSystem.spacingSm),
+            padding: const EdgeInsets.all(DesignSystem.spacingSm),
             decoration: BoxDecoration(
               color: isSelected ? data.color.withOpacity(0.1) : Colors.transparent,
               borderRadius: BorderRadius.circular(DesignSystem.radiusSm),
@@ -232,7 +232,7 @@ class _ProfessionalPieChartState extends State<ProfessionalPieChart>
                     borderRadius: BorderRadius.circular(DesignSystem.radiusXs),
                   ),
                 ),
-                SizedBox(width: DesignSystem.spacingSm),
+                const SizedBox(width: DesignSystem.spacingSm),
                 Expanded(
                   child: Column(
                     crossAxisAlignment: CrossAxisAlignment.start,
@@ -262,7 +262,7 @@ class _ProfessionalPieChartState extends State<ProfessionalPieChart>
 
   Widget _buildCenterInfo() {
     return Container(
-      padding: EdgeInsets.all(DesignSystem.spacingMd),
+      padding: const EdgeInsets.all(DesignSystem.spacingMd),
       decoration: BoxDecoration(
         color: AppTheme.primaryColor.withOpacity(0.1),
         borderRadius: BorderRadius.circular(DesignSystem.radiusMd),
@@ -279,7 +279,7 @@ class _ProfessionalPieChartState extends State<ProfessionalPieChart>
               color: AppTheme.textSecondary,
             ),
           ),
-          SizedBox(height: DesignSystem.spacingXs),
+          const SizedBox(height: DesignSystem.spacingXs),
           Text(
             widget.centerText!,
             style: DesignSystem.headlineMedium.copyWith(