calfw capture: smart time prompt (single/multi-day, timed/all-day)

- Start time prompt: empty = all-day, HH:MM = timed
- End prompt: HH:MM (same day), YYYY-MM-DD (multi-day), YYYY-MM-DD HH:MM
- All formats match what ox-icalendar/org-caldav export correctly
- Set org-icalendar-timezone to Europe/Prague
- Set org-icalendar-with-timestamps to active

config.el

@@ -324,6 +324,11 @@
            "* %?\n%(my/calfw-capture-timestamp)\n"
            :empty-lines 1))))
 
+;; Ensure ox-icalendar exports active timestamps with times correctly
+(after! ox-icalendar
+  (setq org-icalendar-with-timestamps 'active
+        org-icalendar-timezone "Europe/Prague"))
+
 
 ;;; ============================================================
 ;;; ORG MODE — AGENDA
@@ -1593,18 +1598,55 @@ Skip for beamer exports — beamer uses adjustbox on plain tabular."
   :demand t
   :config
   ;; org-capture integration: "a" to add event on selected date
-  ;; Prompts for time range; empty = all-day event
+  ;; Prompts for start/end time; empty = all-day event
+  ;; Uses active timestamp with time range for timed events,
+  ;; or date-range (-->--) for multi-day events.
   (defun my/calfw-capture-timestamp ()
-    "Build org timestamp for selected calfw date with optional time prompt."
+    "Build org timestamp for selected calfw date with optional time prompt.
+Formats matching what org-caldav/ox-icalendar export correctly:
+  - All-day single: <2026-02-26 Thu>
+  - Timed single day: <2026-02-26 Thu 14:00-15:30>
+  - All-day multi: <2026-02-26 Thu>--<2026-02-28 Sat>
+  - Timed multi-day: <2026-02-26 Thu 15:00>--<2026-02-28 Sat 22:00>"
     (let* ((date (calfw-cursor-to-nearest-date))
            (y (calendar-extract-year date))
            (m (calendar-extract-month date))
            (d (calendar-extract-day date))
            (dow (calendar-day-name (encode-time 0 0 0 d m y) nil t))
-           (time (read-string "Time (e.g. 14:00-15:30, empty=all-day): ")))
+           (start-time (read-string "Start time (HH:MM, empty=all-day): "))
-      (if (string-empty-p time)
+           (end-input (unless (string-empty-p start-time)
-          (format "<%04d-%02d-%02d %s>" y m d dow)
+                        (read-string "End time or end date (HH:MM / YYYY-MM-DD / YYYY-MM-DD HH:MM, empty=same day open): "))))
-        (format "<%04d-%02d-%02d %s %s>" y m d dow time))))
+      (cond
+       ;; All-day event (no time given)
+       ((string-empty-p start-time)
+        (let ((end-date (read-string "End date for multi-day (YYYY-MM-DD, empty=single day): ")))
+          (if (string-empty-p end-date)
+              (format "<%04d-%02d-%02d %s>" y m d dow)
+            (let* ((parsed (parse-time-string (concat end-date " 00:00")))
+                   (ed (nth 3 parsed)) (em (nth 4 parsed)) (ey (nth 5 parsed))
+                   (edow (calendar-day-name (encode-time 0 0 0 ed em ey) nil t)))
+              (format "<%04d-%02d-%02d %s>--<%04d-%02d-%02d %s>" y m d dow ey em ed edow)))))
+       ;; Timed event - check if end contains a date (multi-day)
+       ((and end-input (not (string-empty-p end-input))
+             (string-match "^[0-9]\\{4\\}-[0-9]\\{2\\}-[0-9]\\{2\\}" end-input))
+        ;; Multi-day with times
+        (let* ((end-time-part (if (string-match " \\([0-9]\\{2\\}:[0-9]\\{2\\}\\)" end-input)
+                                  (match-string 1 end-input) ""))
+               (end-date-part (substring end-input 0 10))
+               (parsed (parse-time-string (concat end-date-part " 00:00")))
+               (ed (nth 3 parsed)) (em (nth 4 parsed)) (ey (nth 5 parsed))
+               (edow (calendar-day-name (encode-time 0 0 0 ed em ey) nil t)))
+          (if (string-empty-p end-time-part)
+              (format "<%04d-%02d-%02d %s %s>--<%04d-%02d-%02d %s>"
+                      y m d dow start-time ey em ed edow)
+            (format "<%04d-%02d-%02d %s %s>--<%04d-%02d-%02d %s %s>"
+                    y m d dow start-time ey em ed edow end-time-part))))
+       ;; Same-day timed event with end time (HH:MM)
+       ((and end-input (not (string-empty-p end-input)))
+        (format "<%04d-%02d-%02d %s %s-%s>" y m d dow start-time end-input))
+       ;; Same-day timed event, no end time
+       (t
+        (format "<%04d-%02d-%02d %s %s>" y m d dow start-time)))))
 
   (setq calfw-org-capture-template
         '("c" "Calendar event" entry