feat: initial implementation of iCalendar to Remind converter

- Add project scaffolding (dune, dune-project, opam, .ocamlformat)
- Implement basic parsing and handling of iCalendar events
- Add event predicates for common event types (all-day, timed,
  recurrence, exceptions)
- Add transformation logic to map iCalendar events to Remind format
  (stub implementation)
- Provide utilities for extracting event details and converting
  dates/times
- Set up executable entrypoint and command-line interface using Cmdliner
- Include Remind event type definitions and helpers

bin/eventTransformer.ml

@@ -0,0 +1,15 @@
+let default_implementation = Remind.Omit (Ptime.epoch |> Ptime.to_date)
+
+let remind_of_event (ev : Icalendar.event) : Remind.event =
+  let found =
+    ListLabels.fold_left ~init:[] EventPredicates.all_predicates ~f:(fun acc (pred, desc) ->
+        if pred ev then desc :: acc else acc)
+    |> List.rev
+  in
+  if List.length found > 0
+  then begin
+    Printf.printf "  󰧓 ⇒ matches these predicates:\n";
+    List.iter (fun d -> Printf.printf "    - %s\n" (EventPredicates.show_event_description d)) found;
+    Printf.printf "\n"
+  end;
+  default_implementation