refactor(predicates): return features instead of bool, add P00/P11 predicates

- Change predicate return type from `bool` to `features list option` to
  carry extracted event data (Summary, Day_start, Multi_day) alongside
  match results
- Add `features` type with Generic_feature_presence, Summary, Day_start,
  Multi_day variants
- Add P00 (has_summary) and P11 (override_events) predicates
- Remove large commented-out icalendar/ptime type definitions
- Refactor main.ml to group events by UID using a Map
- Add get_y_m_d_from_timedesc helper to Utils

bin/eventTransformer.ml

@@ -3,13 +3,19 @@ let default_implementation = Remind.make_default_event "TODO: implement conversi
 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)
+        match pred ev with
+        | Some feats -> (desc, feats) :: acc
+        | None -> 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 "  \u{f04d3} \u{21d2} matches these predicates:\n";
+    ListLabels.iter
+      ~f:(fun (desc, features) ->
+        Printf.printf "    - %s\n" (EventPredicates.show_event_description desc);
+        ListLabels.iter ~f:(fun feat -> Printf.printf "      - %s\n" (EventPredicates.show_features feat)) features)
+      found;
     Printf.printf "\n"
   end;
   default_implementation