feat: add multi-environment support (development, staging, production)

- Replace dotenv with compile-time dart-define-from-file config per flavor
  - Add Android product flavors with applicationIdSuffix and per-flavor AndroidManifest
  - Add iOS build configurations, schemes, per-flavor plists and entitlements
  - Configure ProGuard rules for R8 compatibility with Entrust/Antelop SDK
  - Restructure assets into shared/ and per-flavor directories
  - Generate per-flavor launcher icons for Android and iOS
  - Refactor app initialization into initApp() with per-flavor entry points
  - Update asset paths across auth, home, profile, splash modules and sf_shared

modules/auth/lib/src/features/device_setup/presentation/steps/link_info_step.dart

@@ -29,7 +29,7 @@ class LinkInfoStepScreen extends ConsumerWidget {
 
         const SizedBox(height: 25),
 
-        SvgPicture.asset("assets/images/ui/formulario.svg"),
+        SvgPicture.asset("assets/shared/images/formulario.svg"),
 
         const SizedBox(height: 40),
 

modules/auth/lib/src/features/device_setup/presentation/steps/scan_strap_and_watch_step.dart

@@ -135,7 +135,7 @@ class ScanStrapAndWatchStepScreen extends ConsumerWidget {
               ),
               child: Center(
                 child: SvgPicture.asset(
-                  "assets/images/ui/qr.svg",
+                  "assets/shared/images/qr.svg",
                   width: 90,
                   height: 90,
                   fit: BoxFit.contain,

modules/auth/lib/src/features/link_phone/presentation/widgets/loading_screen.dart

@@ -14,7 +14,7 @@ class LoadingScreen extends StatelessWidget{
             spacing: 50,
             children: [
               Spacer(flex: 8),
-              SvgPicture.asset("assets/images/ui/logo_sf.svg"),
+              SvgPicture.asset("assets/shared/images/logo_sf.svg"),
               AppLoadingIndicator(),
               Spacer(flex: 10)
             ],

modules/auth/lib/src/features/onboarding/domain/onboarding_page.dart

@@ -14,17 +14,17 @@ class OnboardingPage {
 
 const List<OnboardingPage> onboardingPages = <OnboardingPage>[
   OnboardingPage(
-    image: 'assets/images/ui/bienvenida_paso1.svg',
+    image: 'assets/shared/images/bienvenida_paso1.svg',
     title: I18n.onboardingTitle1,
     subtitle: I18n.onboardingSubtitle1,
   ),
   OnboardingPage(
-    image: 'assets/images/ui/bienvenida_paso2.svg',
+    image: 'assets/shared/images/bienvenida_paso2.svg',
     title: I18n.onboardingTitle2,
     subtitle: I18n.onboardingSubtitle2,
   ),
   OnboardingPage(
-    image: 'assets/images/ui/bienvenida_paso3.svg',
+    image: 'assets/shared/images/bienvenida_paso3.svg',
     title: I18n.onboardingTitle3,
     subtitle: I18n.onboardingSubtitle3,
   ),