feat: implement AppAnimatedSwitcher for consistent page transitions

lib/components/app_animated_switcher.dart

@@ -0,0 +1,42 @@
+import 'package:flutter/material.dart';
+import 'package:shop/constants.dart';
+
+/// Generic AnimatedSwitcher wrapper used to keep page transitions consistent.
+class AppAnimatedSwitcher extends StatelessWidget {
+  const AppAnimatedSwitcher({
+    super.key,
+    required this.child,
+    this.duration = defaultDuration,
+    this.switchInCurve = Curves.easeOut,
+    this.switchOutCurve = Curves.easeIn,
+    this.offset = const Offset(0, 0.04),
+  });
+
+  final Widget child;
+  final Duration duration;
+  final Curve switchInCurve;
+  final Curve switchOutCurve;
+  final Offset offset;
+
+  @override
+  Widget build(BuildContext context) {
+    return AnimatedSwitcher(
+      duration: duration,
+      switchInCurve: switchInCurve,
+      switchOutCurve: switchOutCurve,
+      transitionBuilder: (child, animation) {
+        final offsetAnimation =
+            Tween<Offset>(begin: offset, end: Offset.zero).animate(animation);
+
+        return FadeTransition(
+          opacity: animation,
+          child: SlideTransition(
+            position: offsetAnimation,
+            child: child,
+          ),
+        );
+      },
+      child: child,
+    );
+  }
+}

lib/entry_point.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_svg/flutter_svg.dart';
+import 'package:shop/components/app_animated_switcher.dart';
 import 'package:shop/constants.dart';
 import 'package:shop/route/screen_export.dart';
 
@@ -75,24 +76,7 @@ class _EntryPointState extends State<EntryPoint> {
           ),
         ],
       ),
-      // body: _pages[_currentIndex],
-      body: AnimatedSwitcher(
-        duration: defaultDuration,
-        switchInCurve: Curves.easeOut,
-        switchOutCurve: Curves.easeIn,
-        transitionBuilder: (child, animation) {
-          final offsetAnimation = Tween<Offset>(
-            begin: const Offset(0, 0.04),
-            end: Offset.zero,
-          ).animate(animation);
-          return FadeTransition(
-            opacity: animation,
-            child: SlideTransition(
-              position: offsetAnimation,
-              child: child,
-            ),
-          );
-        },
+      body: AppAnimatedSwitcher(
         child: KeyedSubtree(
           key: ValueKey<int>(_currentIndex),
           child: _pages[_currentIndex],

lib/screens/main_screen.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
+import 'package:shop/components/app_animated_switcher.dart';
 import 'package:shop/constants.dart';
 import 'package:shop/providers/cart_provider.dart';
 import 'package:shop/screens/category/views/categories_list_screen.dart';
@@ -27,24 +28,7 @@ class _MainScreenState extends State<MainScreen> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      body: AnimatedSwitcher(
-        duration: defaultDuration,
-        switchInCurve: Curves.easeOut,
-        switchOutCurve: Curves.easeIn,
-        transitionBuilder: (child, animation) {
-          final offsetAnimation = Tween<Offset>(
-            begin: const Offset(0, 0.04),
-            end: Offset.zero,
-          ).animate(animation);
-
-          return FadeTransition(
-            opacity: animation,
-            child: SlideTransition(
-              position: offsetAnimation,
-              child: child,
-            ),
-          );
-        },
+      body: AppAnimatedSwitcher(
         child: KeyedSubtree(
           key: ValueKey<int>(_selectedIndex),
           child: _screens[_selectedIndex],