Integrate Google Maps Places Autocomplete for hub address validation and enhance UI button styles

apps/mobile/packages/design_system/lib/src/widgets/ui_button.dart

@@ -132,10 +132,14 @@ class UiButton extends StatelessWidget {
   @override
   /// Builds the button UI.
   Widget build(BuildContext context) {
+    final ButtonStyle? mergedStyle = style != null 
+        ? _getSizeStyle().merge(style) 
+        : _getSizeStyle();
+    
     final Widget button = buttonBuilder(
       context,
       onPressed,
-      style,
+      mergedStyle,
       _buildButtonContent(),
     );
 
@@ -146,6 +150,65 @@ class UiButton extends StatelessWidget {
     return button;
   }
 
+  /// Gets the style based on the button size.
+  ButtonStyle _getSizeStyle() {
+    switch (size) {
+      case UiButtonSize.extraSmall:
+        return ButtonStyle(
+          padding: WidgetStateProperty.all(
+            const EdgeInsets.symmetric(
+              horizontal: UiConstants.space2,
+              vertical: UiConstants.space1,
+            ),
+          ),
+          minimumSize: WidgetStateProperty.all(const Size(0, 28)),
+          maximumSize: WidgetStateProperty.all(const Size(double.infinity, 28)),
+          textStyle: WidgetStateProperty.all(
+            const TextStyle(fontSize: 12, fontWeight: FontWeight.w500),
+          ),
+        );
+      case UiButtonSize.small:
+        return ButtonStyle(
+          padding: WidgetStateProperty.all(
+            const EdgeInsets.symmetric(
+              horizontal: UiConstants.space3,
+              vertical: UiConstants.space2,
+            ),
+          ),
+          minimumSize: WidgetStateProperty.all(const Size(0, 36)),
+          maximumSize: WidgetStateProperty.all(const Size(double.infinity, 36)),
+          textStyle: WidgetStateProperty.all(
+            const TextStyle(fontSize: 13, fontWeight: FontWeight.w500),
+          ),
+        );
+      case UiButtonSize.medium:
+        return ButtonStyle(
+          padding: WidgetStateProperty.all(
+            const EdgeInsets.symmetric(
+              horizontal: UiConstants.space4,
+              vertical: UiConstants.space3,
+            ),
+          ),
+          minimumSize: WidgetStateProperty.all(const Size(0, 44)),
+          maximumSize: WidgetStateProperty.all(const Size(double.infinity, 44)),
+        );
+      case UiButtonSize.large:
+        return ButtonStyle(
+          padding: WidgetStateProperty.all(
+            const EdgeInsets.symmetric(
+              horizontal: UiConstants.space6,
+              vertical: UiConstants.space4,
+            ),
+          ),
+          minimumSize: WidgetStateProperty.all(const Size(0, 52)),
+          maximumSize: WidgetStateProperty.all(const Size(double.infinity, 52)),
+          textStyle: WidgetStateProperty.all(
+            const TextStyle(fontSize: 16, fontWeight: FontWeight.w600),
+          ),
+        );
+    }
+  }
+
   /// Builds the button content with optional leading and trailing icons.
   Widget _buildButtonContent() {
     if (child != null) {
@@ -229,6 +292,9 @@ class UiButton extends StatelessWidget {
 
 /// Defines the size of a [UiButton].
 enum UiButtonSize {
+  /// Extra small button (very compact)
+  extraSmall,
+
   /// Small button (compact)
   small,