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_line_chart.dart

@@ -70,7 +70,7 @@ class _ProfessionalLineChartState extends State<ProfessionalLineChart>
       crossAxisAlignment: CrossAxisAlignment.start,
       children: [
         _buildHeader(),
-        SizedBox(height: DesignSystem.spacingLg),
+        const SizedBox(height: DesignSystem.spacingLg),
         Expanded(
           child: _buildChart(),
         ),
@@ -89,7 +89,7 @@ class _ProfessionalLineChartState extends State<ProfessionalLineChart>
           ),
         ),
         if (widget.subtitle != null) ...[
-          SizedBox(height: DesignSystem.spacingXs),
+          const SizedBox(height: DesignSystem.spacingXs),
           Text(
             widget.subtitle!,
             style: DesignSystem.bodyMedium.copyWith(
@@ -111,7 +111,7 @@ class _ProfessionalLineChartState extends State<ProfessionalLineChart>
               touchTooltipData: LineTouchTooltipData(
                 tooltipBgColor: AppTheme.textPrimary.withOpacity(0.9),
                 tooltipRoundedRadius: DesignSystem.radiusSm,
-                tooltipPadding: EdgeInsets.all(DesignSystem.spacingSm),
+                tooltipPadding: const EdgeInsets.all(DesignSystem.spacingSm),
                 getTooltipItems: (List<LineBarSpot> touchedBarSpots) {
                   return touchedBarSpots.map((barSpot) {
                     final data = widget.data[barSpot.x.toInt()];
@@ -239,7 +239,7 @@ class _ProfessionalLineChartState extends State<ProfessionalLineChart>
     return SideTitleWidget(
       axisSide: meta.axisSide,
       child: Padding(
-        padding: EdgeInsets.only(top: DesignSystem.spacingXs),
+        padding: const EdgeInsets.only(top: DesignSystem.spacingXs),
         child: Text(
           data.label,
           style: DesignSystem.labelSmall.copyWith(