feat: Implement initial filtering for agent search from the home screen, enable footer navigation, and add provider stability checks.

lib/core/widgets/s3_image.dart

@@ -1,5 +1,6 @@
 import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
+import 'package:shimmer/shimmer.dart';
 import 'package:real_estate_mobile/core/utils/image_url_resolver.dart';
 
 /// Displays an image from an S3 key or full URL.
@@ -9,6 +10,7 @@ class S3Image extends StatefulWidget {
   final double? width;
   final double? height;
   final BoxFit fit;
+  final Alignment alignment;
   final Widget Function(BuildContext context)? placeholder;
   final Widget Function(BuildContext context)? errorWidget;
 
@@ -18,6 +20,7 @@ class S3Image extends StatefulWidget {
     this.width,
     this.height,
     this.fit = BoxFit.cover,
+    this.alignment = Alignment.center,
     this.placeholder,
     this.errorWidget,
   });
@@ -67,15 +70,22 @@ class _S3ImageState extends State<S3Image> {
     }
   }
 
-  Widget _buildPlaceholder(BuildContext context) {
-    return widget.placeholder?.call(context) ?? Container(
-      width: widget.width,
-      height: widget.height,
-      color: const Color(0xFFC4D9D4),
-      child: const Center(child: CircularProgressIndicator(strokeWidth: 2)),
+  Widget _buildShimmerPlaceholder() {
+    return Shimmer.fromColors(
+      baseColor: const Color(0xFFE0E0E0),
+      highlightColor: const Color(0xFFF5F5F5),
+      child: Container(
+        width: widget.width,
+        height: widget.height,
+        color: Colors.white,
+      ),
     );
   }
 
+  Widget _buildPlaceholder(BuildContext context) {
+    return widget.placeholder?.call(context) ?? _buildShimmerPlaceholder();
+  }
+
   Widget _buildError(BuildContext context) {
     return widget.errorWidget?.call(context) ?? Container(
       width: widget.width,
@@ -95,6 +105,7 @@ class _S3ImageState extends State<S3Image> {
       width: widget.width,
       height: widget.height,
       fit: widget.fit,
+      alignment: widget.alignment,
       placeholder: (ctx, _) => _buildPlaceholder(ctx),
       errorWidget: (ctx, _, __) => _buildError(ctx),
     );