refactor: remove redundant AnimatedSwitcher and update routing transitions to use slide animations for detail screens

lib/core/widgets/app_shell.dart

@@ -83,22 +83,7 @@ class _AppShellState extends State<AppShell> {
             child: const HomeHeader(),
           ),
           Expanded(
-            child: AnimatedSwitcher(
-              duration: const Duration(milliseconds: 250),
-              switchInCurve: Curves.easeOut,
-              switchOutCurve: Curves.easeIn,
-              transitionBuilder: (child, animation) {
-                return FadeTransition(
-                  opacity: animation,
-                  child: child,
-                );
-              },
-              child: SizedBox(
-                key: ValueKey(widget.child.runtimeType.hashCode ^
-                    widget.child.hashCode),
-                child: widget.child,
-              ),
-            ),
+            child: widget.child,
           ),
         ],
       ),