fix(accessibility): use React Native-supported 'button' role for toasts

Replace unsupported 'alert'/'status' roles with 'button' in TOAST_TYPE_TO_ROLE,
update Toast's fallback role to 'button', and adjust tests accordingly. Announcements
continue to be handled via accessibilityLiveRegion.

Author: mCodex

src/components/Toast.tsx

@@ -196,7 +196,7 @@ const Toast: React.FC<ToastProps> = ({
 
     // Determine accessibility role (can be customized via config)
     const roleMap = config.accessibility?.roleMap;
-    const role = roleMap?.[type] ?? TOAST_TYPE_TO_ROLE[type] ?? 'alert';
+    const role = roleMap?.[type] ?? TOAST_TYPE_TO_ROLE[type] ?? 'button';
 
     // Determine live region (polite for non-urgent, assertive for urgent)
     const liveRegion = TOAST_TYPE_TO_LIVE_REGION[type] ?? 'polite';

src/utils/__tests__/accessibility.test.ts

@@ -352,10 +352,10 @@ describe('accessibility utilities', () => {
 
   describe('constants', () => {
     it('should have all toast types mapped to roles', () => {
-      expect(TOAST_TYPE_TO_ROLE.info).toBe('alert');
-      expect(TOAST_TYPE_TO_ROLE.success).toBe('status');
-      expect(TOAST_TYPE_TO_ROLE.warning).toBe('alert');
-      expect(TOAST_TYPE_TO_ROLE.error).toBe('alert');
+      expect(TOAST_TYPE_TO_ROLE.info).toBe('button');
+      expect(TOAST_TYPE_TO_ROLE.success).toBe('button');
+      expect(TOAST_TYPE_TO_ROLE.warning).toBe('button');
+      expect(TOAST_TYPE_TO_ROLE.error).toBe('button');
     });
 
     it('should have all toast types mapped to live regions', () => {

src/utils/accessibility.ts

@@ -16,15 +16,20 @@ import type { ToastType, ToastMessage } from '../types';
 
 /**
  * Toast type to accessibility role mapping.
- * Maps semantic toast types to appropriate ARIA roles for screen readers.
+ * Maps semantic toast types to appropriate roles supported by React Native.
+ * Note: React Native Pressable only supports: button, link, header, search, image,
+ * imagebutton, keyboardkey, text, adjustable, checkbox, combobox, menu, menuitem,
+ * progressbar, radio, scrollbar, spinbutton, switch, tab
+ *
+ * WCAG alert/status roles are announced via accessibilityLiveRegion instead.
  *
  * @constant
  */
 export const TOAST_TYPE_TO_ROLE: Record<ToastType, string> = {
-  info: 'alert',
-  success: 'status',
-  warning: 'alert',
-  error: 'alert',
+  info: 'button',
+  success: 'button',
+  warning: 'button',
+  error: 'button',
 };
 
 /**