events: api.sx — public events facade + 14 tests (Phase 1 complete)

Immutable store ({:events :bookings}) over calendar+availability:
ev/schedule, ev/book, ev/agenda, ev/agenda-for, ev/free?, ev/next-free,
ev/conflicts. Availability queries auto-widen expansion by longest event.
73/73 green. Phase 1 done.

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

lib/events/tests/api.sx

@@ -0,0 +1,176 @@
+;; lib/events/tests/api.sx — public events facade (schedule/agenda/free/book).
+
+(define ev-api-pass 0)
+(define ev-api-fail 0)
+(define ev-api-failures (list))
+
+(define
+  ev-api-check!
+  (fn
+    (name got expected)
+    (if
+      (= got expected)
+      (set! ev-api-pass (+ ev-api-pass 1))
+      (do
+        (set! ev-api-fail (+ ev-api-fail 1))
+        (append!
+          ev-api-failures
+          (str name "\n    expected: " expected "\n    got:      " got))))))
+
+;; A store with a weekly yoga class (Mon+Wed 18:00, 60m, 4 occurrences).
+(define
+  ev-api-store
+  (fn
+    ()
+    (ev/schedule
+      (ev/empty)
+      (quote yoga)
+      (ev-dt 2026 6 1 18 0)
+      60
+      {:freq :weekly :count 4 :byday (list 0 2)}
+      20)))
+
+(define
+  ev-api-run-all!
+  (fn
+    ()
+    (let
+      ((s0 (ev-api-store)))
+      (let
+        ((occs (ev/agenda s0 (ev-date 2026 6 1) (ev-date 2026 7 1))))
+        (let
+          ((s1 (ev/book (ev/book s0 (quote nia) (ev-occ-key (first occs))) (quote nia) (ev-occ-key (first (rest occs))))))
+          (do
+            (ev-api-check!
+              "agenda expands weekly class to four occurrences"
+              (map (fn (o) (ev-dt->civil (get o :start))) occs)
+              (list
+                (list 2026 6 1)
+                (list 2026 6 3)
+                (list 2026 6 8)
+                (list 2026 6 10)))
+            (ev-api-check!
+              "empty store has empty agenda"
+              (ev/agenda
+                (ev/empty)
+                (ev-date 2026 6 1)
+                (ev-date 2026 7 1))
+              (list))
+            (ev-api-check!
+              "max duration reflects scheduled events"
+              (ev/store-max-duration s0)
+              60)
+            (ev-api-check!
+              "max duration of empty store is zero"
+              (ev/store-max-duration (ev/empty))
+              0)
+            (ev-api-check!
+              "agenda-for lists only booked occurrences"
+              (map
+                (fn (o) (ev-dt->civil (get o :start)))
+                (ev/agenda-for
+                  s1
+                  (quote nia)
+                  (ev-date 2026 6 1)
+                  (ev-date 2026 7 1)))
+              (list
+                (list 2026 6 1)
+                (list 2026 6 3)))
+            (ev-api-check!
+              "agenda-for empty for unbooked actor"
+              (ev/agenda-for
+                s1
+                (quote zed)
+                (ev-date 2026 6 1)
+                (ev-date 2026 7 1))
+              (list))
+            (ev-api-check!
+              "free? false during a booked occurrence"
+              (ev/free?
+                s1
+                (quote nia)
+                (ev-dt 2026 6 1 18 30)
+                (ev-dt 2026 6 1 19 0))
+              false)
+            (ev-api-check!
+              "free? true in an open window"
+              (ev/free?
+                s1
+                (quote nia)
+                (ev-dt 2026 6 1 9 0)
+                (ev-dt 2026 6 1 10 0))
+              true)
+            (ev-api-check!
+              "free? half-open at occurrence end"
+              (ev/free?
+                s1
+                (quote nia)
+                (ev-dt 2026 6 1 19 0)
+                (ev-dt 2026 6 1 20 0))
+              true)
+            (ev-api-check!
+              "free? true for an actor who booked nothing"
+              (ev/free?
+                s1
+                (quote zed)
+                (ev-dt 2026 6 1 18 0)
+                (ev-dt 2026 6 1 19 0))
+              true)
+            (ev-api-check!
+              "next-free skips the booked slot to the hour after"
+              (ev-dt-tod
+                (ev/next-free
+                  s1
+                  (quote nia)
+                  (ev-dt
+                    2026
+                    6
+                    1
+                    18
+                    0)
+                  60
+                  (ev-dt
+                    2026
+                    6
+                    1
+                    23
+                    0)))
+              (* 19 60))
+            (ev-api-check!
+              "next-free returns `after` when already open"
+              (ev/next-free
+                s1
+                (quote nia)
+                (ev-dt 2026 6 1 9 0)
+                60
+                (ev-dt 2026 6 1 18 0))
+              (ev-dt 2026 6 1 9 0))
+            (ev-api-check!
+              "no conflict among disjoint bookings"
+              (ev/has-conflict?
+                s1
+                (quote nia)
+                (ev-date 2026 6 1)
+                (ev-date 2026 7 1))
+              false)
+            (let
+              ((sc (ev/book (ev/schedule s1 (quote talk) (ev-dt 2026 6 1 18 30) 60 nil 5) (quote nia) (ev-occ-key (ev-occ (quote talk) (ev-dt 2026 6 1 18 30) 60)))))
+              (ev-api-check!
+                "overlapping second booking creates a conflict"
+                (ev/has-conflict?
+                  sc
+                  (quote nia)
+                  (ev-date 2026 6 1)
+                  (ev-date 2026 7 1))
+                true))))))))
+
+(define
+  ev-api-tests-run!
+  (fn
+    ()
+    (do
+      (set! ev-api-pass 0)
+      (set! ev-api-fail 0)
+      (set! ev-api-failures (list))
+      (ev-api-run-all!)
+      {:failures ev-api-failures :total (+ ev-api-pass ev-api-fail) :passed ev-api-pass :failed ev-api-fail})))