vdirsyncer: add local read-only news

Announce the localReadOnly option to users who enable the vdirsyncer module.

Author: khaneliman

modules/misc/news/2026/08/2026-08-12_07-12-58.nix

@@ -0,0 +1,12 @@
+{ config, ... }:
+{
+  time = "2026-08-12T12:12:58+00:00";
+  condition = config.programs.vdirsyncer.enable;
+  message = ''
+    Vdirsyncer can now treat local calendar and contact storages as read-only.
+
+    Set `accounts.calendar.accounts.<name>.vdirsyncer.localReadOnly` or
+    `accounts.contact.accounts.<name>.vdirsyncer.localReadOnly` to configure
+    this behavior.
+  '';
+}