restructure: move el compiler content into lang/

lang/tests/calendar/examples/cycle-30hr.el

@@ -0,0 +1,20 @@
+// cycle-30hr.el — CycleCalendar with a 30-hour period.
+// Two CalendarTimes 15 hours apart should have cycle_phase differ by 0.5.
+// We compare phases via float subtraction with format_float for determinism.
+
+fn run_test() -> String {
+    let period: Duration = 30.hours
+    let cal: Calendar = cycle_calendar(period)
+    let base: Instant = unix_seconds(0)
+    let later: Instant = base + 15.hours
+    let ct1: CalendarTime = in_calendar(base, cal)
+    let ct2: CalendarTime = in_calendar(later, cal)
+    let p1: Float = cal_cycle_phase(ct1)
+    let p2: Float = cal_cycle_phase(ct2)
+    let diff: Float = p2 - p1
+    return format_float(diff, 1)
+}
+
+fn main() -> Void {
+    println(run_test())
+}