fix(app): SVG im Vollbild via SvgUri rendern (statt Image) — preserveAspectRatio damit nicht gestreckt

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

android/src/screens/ChatScreen.tsx

@@ -1363,11 +1363,17 @@ const ChatScreen: React.FC = () => {
           onPress={() => setFullscreenImage(null)}
         >
           {fullscreenImage && (
-            <Image
-              source={{ uri: fullscreenImage }}
-              style={styles.fullscreenImage}
-              resizeMode="contain"
-            />
+            /\.svg(?:\?|$)/i.test(fullscreenImage) ? (
+              <View style={styles.fullscreenImage}>
+                <SvgUri uri={fullscreenImage} width="100%" height="100%" preserveAspectRatio="xMidYMid meet" />
+              </View>
+            ) : (
+              <Image
+                source={{ uri: fullscreenImage }}
+                style={styles.fullscreenImage}
+                resizeMode="contain"
+              />
+            )
           )}
         </TouchableOpacity>
       </Modal>