fuzz-target-every-parse: the §3.2 differential target — three parsers + skip_forward through the doc-hidden surfaces via shared invariants, 66 committed seeds + gitignore negation + README row; two real skip_forward findings fixed inline (division-by-zero/negative-interval wrap on sqlite+mem, i64 gap subtraction overflow on all three engines incl. pg) and registered as PROVENANCE D-38

alkstore-mem/src/scheduler.rs

@@ -252,8 +252,8 @@ fn fire_due(sched: &mut ScheduleState, queues: &mut QueueState, state: &State, n
 /// in the future, grid-aligned (the schedule row's advance makes the
 /// gap inspectable).
 pub fn skip_forward(next_fire_at: i64, now: i64, interval: i64) -> i64 {
-    let gap = (now - next_fire_at) as i128;
-    let interval = interval as i128;
+    let gap = now as i128 - next_fire_at as i128;
+    let interval = interval.max(1) as i128;
     let next = (next_fire_at as i128) + (gap / interval + 1) * interval;
     if next > i64::MAX as i128 {
         i64::MAX