events: Phase 1 calendar — DAILY/WEEKLY RRULE expansion + 24 tests

Civil date arithmetic (Hinnant), integer epoch-minute datetimes, bounded
windowed RRULE expansion (DAILY/WEEKLY with INTERVAL/COUNT/UNTIL/BYDAY),
multi-event merge. Conformance harness + scoreboard wired.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

plans/events-on-sx.md

@@ -18,7 +18,7 @@ capacity rules, transactional booking, and a flow-driven notification dispatcher
 
 ## Status (rolling)
 
-`bash lib/events/conformance.sh` → **0/0** (not yet started)
+`bash lib/events/conformance.sh` → **24/24** (Phase 1: calendar recurrence)
 
 ## Ground rules
 
@@ -54,7 +54,8 @@ lib/events/api.sx ── (events/schedule) (events/book) (events/agenda) ──
 ```
 
 ## Phase 1 — Calendar + recurrence
-- [ ] `calendar.sx` — event facts, RRULE expansion in a window
+- [x] `calendar.sx` — event facts, RRULE expansion in a window (DAILY/WEEKLY)
+- [ ] `calendar.sx` — MONTHLY (bymonthday + nth-weekday byday)
 - [ ] `availability.sx` — free/busy rules
 - [ ] `api.sx` + tests + scoreboard + conformance.sh
 
@@ -75,7 +76,15 @@ lib/events/api.sx ── (events/schedule) (events/book) (events/agenda) ──
 - [ ] tests: federated agenda merge
 
 ## Progress log
-(loop fills this in)
+
+- 2026-06-06 — Phase 1 scaffold + calendar recurrence. `calendar.sx`: integer
+  epoch-minute datetimes, Hinnant civil<->day-number conversion, DAILY/WEEKLY
+  RRULE expansion in a bounded (start,end) window with INTERVAL, COUNT (window-
+  independent), UNTIL, BYDAY (weekly). `ev-expand-all` merges + sorts. Wired
+  conformance harness (conf + thin wrapper reusing `lib/guest/conformance.sh`),
+  scoreboard. 24/24 green. MONTHLY deferred to next commit.
 
 ## Blockers
-(loop fills this in)
+
+- None. Substrates present: `lib/datalog` (276/276), `lib/persist`, `lib/flow`
+  all exist — Phase 2/3 unblocked when reached.