fix: sync trusted senders to the address book by default

The "Sync with address book" toggle under Content & Senders was off until
the user turned it on, so senders trusted on the phone stayed in the
local allow-list and never reached the "Trusted Senders" address book the
other devices read. A setting the user never chose now counts as on;
only an explicit opt-out, or a server without contacts, turns it off.

src/components/EmailBodyView.tsx

@@ -12,7 +12,8 @@ import { bodyDocument } from '../lib/email-body-document';
 import { estimateBodyHeight, lastBodyHeight, rememberBodyHeight } from '../lib/body-heights';
 import { parseMailtoUrl } from '../lib/unsubscribe';
 import { fetchInlineImageDataUri } from '../lib/email-export';
-import { isSenderContentTrusted } from '../lib/trusted-senders';
+import { isSenderContentTrusted, isTrustedSendersSyncOn } from '../lib/trusted-senders';
+import { useHasContacts } from '../lib/capabilities';
 import { useSettingsStore } from '../stores/settings-store';
 import { useContactsStore } from '../stores/contacts-store';
 import { useLocaleStore } from '../stores/locale-store';
@@ -527,6 +528,8 @@ export default function EmailBodyView({
   const isSenderTrusted = useSettingsStore((s) => s.isSenderTrusted);
   const addTrustedSender = useSettingsStore((s) => s.addTrustedSender);
   const trustedSendersAddressBook = useSettingsStore((s) => s.trustedSendersAddressBook);
+  const hasContacts = useHasContacts();
+  const syncTrustedSenders = isTrustedSendersSyncOn(trustedSendersAddressBook, hasContacts);
   const emailAlwaysLightMode = useSettingsStore((s) => s.emailAlwaysLightMode);
   const plainTextFont = useSettingsStore((s) => s.plainTextFont);
   const messageSpacing = useSettingsStore((s) => s.messageSpacing);
@@ -540,8 +543,8 @@ export default function EmailBodyView({
   // entries (synced across devices) feed the external-content trust check. We
   // do not create the book here — it is created lazily when a sender is trusted.
   React.useEffect(() => {
-    if (trustedSendersAddressBook && !trustedSendersLoaded) void loadTrustedSendersBook(false);
-  }, [trustedSendersAddressBook, trustedSendersLoaded, loadTrustedSendersBook]);
+    if (syncTrustedSenders && !trustedSendersLoaded) void loadTrustedSendersBook(false);
+  }, [syncTrustedSenders, trustedSendersLoaded, loadTrustedSendersBook]);
   // Most marketing email is authored against a white background, so dark-mode
   // inversion can wreck logos/banners. With this flag the user opts to render
   // emails on a light surface even while the rest of the app is dark; the
@@ -561,7 +564,7 @@ export default function EmailBodyView({
   const text = picked.text;
   const trusted = isSenderContentTrusted(senderEmail, {
     isLocallyTrusted: isSenderTrusted,
-    syncEnabled: trustedSendersAddressBook,
+    syncEnabled: syncTrustedSenders,
     trustedBookEmails: trustedSenderEmails,
   });
 
@@ -721,12 +724,11 @@ export default function EmailBodyView({
   const onLoadImages = () => setAllowOnce(true);
   const onTrustSender = () => {
     if (senderEmail) {
-      // Keep the local allow-list for instant effect. The server-side "Trusted
-      // Senders" address book (synced across devices) is only written when
-      // the user opted into it - otherwise a book would silently appear in
-      // their contacts (matches the webmail).
+      // Keep the local allow-list for instant effect, and file the sender in
+      // the server-side "Trusted Senders" address book (synced across
+      // devices) unless the user turned that off.
       addTrustedSender(senderEmail);
-      if (trustedSendersAddressBook) {
+      if (syncTrustedSenders) {
         void addToTrustedSendersBook(senderEmail).catch(() => {});
       }
       setAllowOnce(true);

src/components/settings/ContentSendersSettings.tsx

@@ -10,6 +10,7 @@ import { useColors } from '../../theme/colors';
 import { useSettingsStore, type ExternalContentPolicy } from '../../stores/settings-store';
 import { useContactsStore } from '../../stores/contacts-store';
 import { useHasContacts } from '../../lib/capabilities';
+import { isTrustedSendersSyncOn } from '../../lib/trusted-senders';
 import { useLocaleStore } from '../../stores/locale-store';
 
 interface TrustedRow {
@@ -49,9 +50,8 @@ export function ContentSendersSettings() {
 
   useEffect(() => { if (!hydrated) void hydrate(); }, [hydrated, hydrate]);
 
-  // Sync stays off until the user turns it on below (null = never chosen):
-  // opening this pane must not change which senders the viewer trusts.
-  const syncEnabled = !!trustedSendersAddressBook && hasContacts;
+  // On unless the user turned it off below (null = never chosen).
+  const syncEnabled = isTrustedSendersSyncOn(trustedSendersAddressBook, hasContacts);
 
   useEffect(() => {
     if (modalOpen && syncEnabled) void loadTrustedSendersBook();
@@ -179,7 +179,7 @@ export function ContentSendersSettings() {
             description={t('settings.email_behavior.trusted_senders.use_address_book_description', 'Store trusted senders in a dedicated "Trusted Senders" address book so they sync across all your devices')}
           >
             <ToggleSwitch
-              checked={!!trustedSendersAddressBook}
+              checked={syncEnabled}
               onChange={(enabled) => {
                 updateSetting('trustedSendersAddressBook', enabled);
                 if (enabled) void loadTrustedSendersBook();