feat: add reusable RefreshControl component

Add minimal RefreshControl wrapper component for pull-to-refresh functionality across screens. Includes theme colors for light/dark mode support.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

components/RefreshControl.tsx

@@ -0,0 +1,21 @@
+import React from 'react'
+import { RefreshControl as RNRefreshControl } from 'react-native'
+
+interface RefreshControlProps {
+  refreshing: boolean
+  onRefresh: () => void
+}
+
+export default function RefreshControl({
+  refreshing,
+  onRefresh,
+}: RefreshControlProps) {
+  return (
+    <RNRefreshControl
+      refreshing={refreshing}
+      onRefresh={onRefresh}
+      tintColor="#F5F5F5"
+      colors={['#F5F5F5']}
+    />
+  )
+}