fix: remove duplicate useRouter() declaration in CalendarScreen

carry-your-live/app/(tabs)/calendar.tsx

@@ -218,7 +218,22 @@ export default function CalendarScreen() {
 
   return (
     <SafeAreaView style={[styles.container, { backgroundColor: theme.background }]}>
-      <Header title="Calendar" showLogo={false} />
+      <Header
+        title="Calendar"
+        showLogo={false}
+        rightAction={
+          <TouchableOpacity
+            onPress={() => router.back()}
+            style={styles.backButton}
+            accessible={true}
+            accessibilityLabel="Back"
+          >
+            <Svg width={20} height={20} viewBox="0 0 24 24">
+              <Path d="M15 18l-6-6 6-6" stroke="currentColor" strokeWidth={2.5} strokeLinecap="round" strokeLinejoin="round" fill="none" />
+            </Svg>
+          </TouchableOpacity>
+        }
+      />
 
       <KeyboardAvoidingView style={styles.kbAvoid} behavior="padding">
       <ScrollView style={styles.scrollBody} showsVerticalScrollIndicator={false} contentContainerStyle={styles.scrollContent}>
@@ -609,6 +624,9 @@ const createStyles = (theme: ThemeColors) => StyleSheet.create({
   emptySubtext: {
     fontSize: 13,
   },
+  backButton: {
+    padding: 8,
+  },
   eventCard: {
     marginHorizontal: 16,
     marginTop: 6,