ocaml: phase 5.1 min_meeting_rooms.ml baseline (8 meetings, min 4 rooms)

Sweep-line algorithm via separately-sorted starts / ends arrays:

  while i < n do
    if starts[i] < ends[j] then begin busy++; rooms = max; i++ end
    else begin busy--; j++ end
  done

  intervals: (0,30) (5,10) (15,20) (10,25) (5,12)
             (20,35) (0,5)  (8,18)

At time 8, meetings (0,30), (5,10), (5,12), (8,18) are all active
simultaneously -> answer = 4.

Tests local helper bound via let (`let bubble a = ...`) for
in-place sort, dual-pointer sweep on parallel ordered event streams.

193 baseline programs total.

lib/ocaml/baseline/expected.json

@@ -121,6 +121,7 @@
   "mortgage.ml": 1073,
   "mst_kruskal.ml": 11,
   "merge_intervals.ml": 12,
+  "min_meeting_rooms.ml": 4,
   "merge_sort.ml": 44,
   "merge_two.ml": 441,
   "min_cost_path.ml": 12,