feat(emacs): add org-caldav UNTIL advice for recurring event end dates

Implements advice around org-caldav-insert-org-event-or-todo that:
- Extracts UNTIL from rrule-props
- Adds DEADLINE without repeater (Org 9.7+ treats as recurrence end)
- Stores :CALDAV_UNTIL: property for reference

Also fixes sync command to work before org is opened by requiring
org explicitly in the sync wrapper.

Closes: x-uv5f.1

home/roles/emacs/doom/config.el

@@ -97,6 +97,7 @@
 (defun my/org-caldav-sync-with-rbw ()
   "Run org-caldav-sync with credentials from rbw embedded in URL."
   (interactive)
+  (require 'org)
   (require 'org-caldav)
   (let* ((password (my/get-rbw-password "nextcloud-caldav"))
          ;; Embed credentials in URL (url-encode password in case of special chars)
@@ -157,6 +158,32 @@
           ;; Note: Create 'tasks' calendar in Nextcloud first, keep it private.
           (:calendar-id "tasks"
            :files ("~/org/todo.org"))))
+
+  ;; Handle UNTIL in recurring events
+  ;; org-caldav ignores UNTIL from RRULE - events repeat forever.
+  ;; This advice extracts UNTIL and adds a DEADLINE without repeater,
+  ;; which Org 9.7+ interprets as the recurrence end date.
+  (defun my/org-caldav-add-until-deadline (orig-fun eventdata-alist)
+    "Advice to add DEADLINE for UNTIL in recurring events."
+    (let ((result (funcall orig-fun eventdata-alist)))
+      (let* ((rrule-props (alist-get 'rrule-props eventdata-alist))
+             (until-str (cadr (assq 'UNTIL rrule-props))))
+        (when until-str
+          (save-excursion
+            (org-back-to-heading t)
+            ;; Store original UNTIL for reference
+            (org-entry-put nil "CALDAV_UNTIL" until-str)
+            ;; Parse UNTIL: format is YYYYMMDD or YYYYMMDDTHHMMSSZ
+            (when (string-match "^\\([0-9]\\{4\\}\\)\\([0-9]\\{2\\}\\)\\([0-9]\\{2\\}\\)" until-str)
+              (let* ((year (string-to-number (match-string 1 until-str)))
+                     (month (string-to-number (match-string 2 until-str)))
+                     (day (string-to-number (match-string 3 until-str)))
+                     (deadline-ts (format "<%d-%02d-%02d>" year month day)))
+                (org-add-planning-info 'deadline deadline-ts))))))
+      result))
+
+  (advice-add 'org-caldav-insert-org-event-or-todo
+              :around #'my/org-caldav-add-until-deadline)
   )
 
 (defun my/get-rbw-password (alias)