fix(emacs): allow org-caldav export with broken links

mu4e message links in todo.org can't be resolved during iCalendar export,
causing sync to abort. Setting org-export-with-broken-links to 'mark'
allows export to continue (broken links get marked in output).

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

home/roles/emacs/doom/config.el

@@ -145,6 +145,9 @@
   (setq org-icalendar-include-todo 'all)
   (setq org-caldav-sync-todo t)
 
+  ;; Allow export with broken links (mu4e links can't be resolved during export)
+  (setq org-export-with-broken-links 'mark)
+
   ;; Calendar-specific configuration
   (setq org-caldav-calendars
         '(;; Personal calendar: two-way sync with family-shared Nextcloud calendar