fix: improve modal behavior on web and Android scrolling

- Restructure ModalBase to use absolute-positioned backdrop behind card
  content, fixing modal stacking issues on web (React Native Web portals)
- Hide EventOverlay when DeleteEventModal is open to prevent z-index
  conflicts on web
- Add nestedScrollEnabled to CardBase ScrollView for Android
- Use TouchableOpacity with delayPressIn in EventCard for scroll-friendly
  touch handling
- Keep eventToDelete state stable during modal fade-out to prevent
  content flash between recurring/single variants
- Fix German umlauts in DeleteEventModal

apps/client/src/components/ModalBase.tsx

@@ -1,4 +1,4 @@
-import { Modal, Pressable } from "react-native";
+import { Modal, Pressable, View } from "react-native";
 import { ReactNode } from "react";
 import { useThemeStore } from "../stores/ThemeStore";
 import { CardBase } from "./CardBase";
@@ -36,19 +36,21 @@ export const ModalBase = ({
       animationType="fade"
       onRequestClose={onClose}
     >
-      <Pressable
-        className="flex-1 justify-center items-center"
-        style={{ backgroundColor: "rgba(0,0,0,0.5)" }}
-        onPress={onClose}
-      >
+      <View className="flex-1 justify-center items-center">
+        {/* Backdrop - absolute positioned behind the card */}
         <Pressable
+          className="absolute inset-0"
+          style={{ backgroundColor: "rgba(0,0,0,0.5)" }}
+          onPress={onClose}
+        />
+        {/* Card content - on top, naturally blocks touches to backdrop */}
+        <View
           className="w-11/12 rounded-2xl overflow-hidden"
           style={{
             backgroundColor: theme.primeBg,
             borderWidth: 4,
             borderColor: theme.borderPrimary,
           }}
-          onPress={(e) => e.stopPropagation()}
         >
           <CardBase
             title={title}
@@ -65,8 +67,8 @@ export const ModalBase = ({
           >
             {children}
           </CardBase>
-        </Pressable>
-      </Pressable>
+        </View>
+      </View>
     </Modal>
   );
 };