Clear ZK viewer secrets and image blob when leaving the page.

frontend/src/views/ViewerView.vue

@@ -79,6 +79,11 @@ onBeforeMount(async () => {
     }
 });
 
+onBeforeUnmount(() => {
+    cleanRefs();
+    viewStore.clearImage();
+});
+
 const onUnlockSubmit = async (): Promise<void> => {
     const payload = zkPayload.value;
     const key = fragmentKey.value;
@@ -104,7 +109,10 @@ const onUnlockSubmit = async (): Promise<void> => {
     }
 };
 
-onBeforeUnmount(() => {
+const cleanRefs = (): void => {
-    viewStore.clearImage();
+    zkPayload.value = null;
-});
+    fragmentKey.value = '';
+    password.value = '';
+    unlockError.value = '';
+};
 </script>