Add E2EE unit tests and improve mobile UI

- Add comprehensive tests for encryption/decryption logic
- Improve error messages for encrypted chat
- Update profile danger zone UI with blur effect
- Refactor typing indicator hook

apps/mobile/app/(app)/_layout.tsx

@@ -50,21 +50,21 @@ function MessageToastPreview({
         currentUserId,
     });
 
-    if (isDecrypting) {
-        return (
-            <Text style={styles.messageToastBody} numberOfLines={1}>
-                Loading...
-            </Text>
-        );
-    }
-
-    if (error) {
-        return (
-            <Text style={styles.messageToastBody} numberOfLines={1}>
-                Failed to load message
-            </Text>
-        );
-    }
+    if (isDecrypting) {
+        return (
+            <Text style={styles.messageToastBody} numberOfLines={1}>
+                Waiting for message...
+            </Text>
+        );
+    }
+
+    if (error) {
+        return (
+            <Text style={styles.messageToastBody} numberOfLines={1}>
+                Encrypted message
+            </Text>
+        );
+    }
 
     return (
         <Text style={styles.messageToastBody} numberOfLines={1}>