Stop dropping the CalDAV login URL after publishing

Publishing a calendar copied caldav_published and caldav_url out of the
response and ignored caldav_login_url, which the same response carries. The
"CalDAV-URL (with login)" field therefore stayed blank until the next full page
load — and that is the URL account-based clients need, so anyone following the
hint underneath it had nothing to copy. The token rotation handler dropped it
the same way.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

frontend/js/calendar.js

@@ -4722,6 +4722,9 @@ function renderCalendarTable() {
         const updated = await api.put(`/local/calendars/${id}`, { caldav_published: newVal });
         cal.caldav_published = updated.caldav_published;
         cal.caldav_url = updated.caldav_url;
+        // The response carries both URLs; dropping this one left the
+        // "with login" field blank until the next full page load.
+        cal.caldav_login_url = updated.caldav_login_url;
         renderCalendarTable();
       } catch (e) { showToast(e.message, true); }
     });
@@ -4741,6 +4744,7 @@ function renderCalendarTable() {
       try {
         const updated = await api.post(`/local/calendars/${id}/dav-token/rotate`);
         cal.caldav_url = updated.caldav_url;
+        cal.caldav_login_url = updated.caldav_login_url;
         renderCalendarTable();
         showToast(t('caldav_token_rotated'));
       } catch (e) { showToast(e.message, true); }