feat: add Daily Digest and Push Notifications toggles to User Profile with corresponding functionality

frontend/vue-app/src/components/profile/UserProfile.vue

@@ -317,17 +317,18 @@ async function resetPassword() {
   }
 }
 
-async function toggleDigest(newValue: boolean) {
+async function toggleDigest(newValue?: boolean) {
+  const value = newValue ?? !emailDigestEnabled.value
   digestError.value = ''
   savingDigest.value = true
   try {
     const res = await fetch('/api/user/profile', {
       method: 'PUT',
       headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ email_digest_enabled: newValue }),
+      body: JSON.stringify({ email_digest_enabled: value }),
     })
     if (!res.ok) throw new Error('Failed to update preference')
-    emailDigestEnabled.value = newValue
+    emailDigestEnabled.value = value
   } catch {
     digestError.value = 'Failed to save notification preference.'
   } finally {