calendar: add recurring events, event management, and safety rules

Add --rrule flag to send with DTSTART/BYDAY validation (RFC 5545).
Add event list (via khal) and event delete (safe single-event removal).
Document safety rules from 2026-03-25 incident: always dry-run recurring
events, never rm .ics files, space out SMTP sends.

skills/calendar/TESTING.md

@@ -293,9 +293,98 @@ $SKILL_DIR/scripts/calendar.sh todo check
 # Should produce no output
 ```
 
-## 14. Regression: Existing Invite Commands
+## 14. Dry Run: Recurring Event (--rrule)
 
-Verify the rename didn't break VEVENT flow.
+Test recurring event generation. Use a date that falls on a Tuesday.
+
+```bash
+# Find next Tuesday
+NEXT_TUE=$(python3 -c "from datetime import date,timedelta; d=date.today(); d+=timedelta((1-d.weekday())%7 or 7); print(d)")
+
+$SKILL_DIR/scripts/calendar.sh send \
+  --to "mail@luyx.org" \
+  --subject "Recurring Test (Tue)" \
+  --summary "Recurring Test (Tue)" \
+  --start "${NEXT_TUE}T14:30:00" \
+  --end "${NEXT_TUE}T15:00:00" \
+  --rrule "FREQ=WEEKLY;COUNT=4;BYDAY=TU" \
+  --dry-run
+```
+
+**Verify:**
+- [ ] ICS has `RRULE:FREQ=WEEKLY;BYDAY=TU;COUNT=4`
+- [ ] DTSTART falls on a Tuesday
+- [ ] No validation errors
+
+## 15. Validation: DTSTART/BYDAY Mismatch
+
+Verify the tool rejects mismatched DTSTART and BYDAY.
+
+```bash
+# This should FAIL — start is on a Tuesday but BYDAY=TH
+$SKILL_DIR/scripts/calendar.sh send \
+  --to "mail@luyx.org" \
+  --subject "Mismatch Test" \
+  --summary "Mismatch Test" \
+  --start "${NEXT_TUE}T09:00:00" \
+  --end "${NEXT_TUE}T09:30:00" \
+  --rrule "FREQ=WEEKLY;COUNT=4;BYDAY=TH" \
+  --dry-run
+```
+
+**Verify:**
+- [ ] Script exits with error
+- [ ] Error message says DTSTART falls on TU but RRULE says BYDAY=TH
+- [ ] Suggests changing --start to a date that falls on TH
+
+## 16. Event List
+
+```bash
+# List upcoming events
+$SKILL_DIR/scripts/calendar.sh event list
+
+# Search by text
+$SKILL_DIR/scripts/calendar.sh event list --search "Calendar Skill Test"
+
+# List with UIDs
+$SKILL_DIR/scripts/calendar.sh event list --format "{uid} {title}"
+```
+
+**Verify:**
+- [ ] Events from earlier tests appear
+- [ ] Search narrows results correctly
+- [ ] UIDs are displayed with --format
+
+## 17. Event Delete
+
+```bash
+# Send a throwaway event first
+$SKILL_DIR/scripts/calendar.sh send \
+  --to "mail@luyx.org" \
+  --subject "Delete Me Event" \
+  --summary "Delete Me Event" \
+  --start "${TEST_DATE}T20:00:00" \
+  --end "${TEST_DATE}T21:00:00"
+
+# Verify it exists
+$SKILL_DIR/scripts/calendar.sh event list --search "Delete Me"
+
+# Delete it
+$SKILL_DIR/scripts/calendar.sh event delete --match "Delete Me Event"
+
+# Verify it's gone
+$SKILL_DIR/scripts/calendar.sh event list --search "Delete Me"
+```
+
+**Verify:**
+- [ ] Event is created and visible
+- [ ] Delete removes exactly one event
+- [ ] Other events are untouched
+- [ ] `vdirsyncer sync` ran after delete
+
+## 18. Regression: Existing Invite Commands
+
+Verify new features didn't break VEVENT flow.
 
 ```bash
 $SKILL_DIR/scripts/calendar.sh send \
@@ -309,7 +398,8 @@ $SKILL_DIR/scripts/calendar.sh send \
 
 **Verify:**
 - [ ] ICS has `BEGIN:VEVENT`, `METHOD:REQUEST`
-- [ ] No errors from the renamed script
+- [ ] No RRULE present (single event)
+- [ ] No errors
 
 ---
 
@@ -347,3 +437,7 @@ todo list
 | `todo` command not found | Install with `uv tool install todoman` |
 | `todo list` errors | Check `~/.config/todoman/config.py` exists and `path` points to tasks dir |
 | Todo not syncing | Check `~/.openclaw/workspace/calendars/tasks/` exists, verify vdirsyncer `cal/tasks` pair |
+| DTSTART/BYDAY mismatch error | `--start` date doesn't fall on the BYDAY day. Change the start date to match |
+| Recurring events on wrong day | DTSTART was not aligned with BYDAY. Delete the event and resend with correct `--start` |
+| SMTP rate limit / EOF error | Too many sends too fast. Wait 10+ seconds between sends (Migadu limit) |
+| Events disappeared after cleanup | **Never use `rm *.ics`** on calendar dirs. Use `event delete --match` instead |