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/main.ml

@@ -1,3 +1,12 @@
+module Map = MoreLabels.Map.Make (String)
+
+type event = Icalendar.event list
+(*
+  We use a list of events here because there can be multiple events with the same UID, and we want to preserve all of
+  them. This is important for handling cases where there are multiple events with the same UID but different properties
+  (e.g., due to updates or recurring events or cancellations).
+*)
+
 let ical2rem ical_file =
   let ic = open_in ical_file in
   let n = in_channel_length ic in
@@ -8,18 +17,30 @@ let ical2rem ical_file =
   match cal_or_error with
   | Error e -> prerr_endline ("Error parsing iCalendar file: " ^ e)
   | Ok (_, components) -> begin
-    let events = ref 0 in
-    List.iter
-      (fun comp ->
-        match comp with
-        | `Event event ->
-          events := !events + 1;
-          let uid = Utils.get_uid event in
-          Printf.printf "󰧓 ⇒ UID: %s\n" uid;
-          Printf.printf "%s\n\n\n" (Icalendar.show_component comp)
-        | _ -> () (* Ignore non-event components *))
-      components;
-    Printf.printf "\nEvents: %d\n" !events;
+    let events_map : event Map.t =
+      ListLabels.fold_left ~init:Map.empty components ~f:(fun acc comp ->
+          match comp with
+          | `Event ev ->
+            let uid = Utils.get_uid ev in
+            let event_list = Map.find_opt uid acc |> Option.value ~default:[] in
+            Map.add ~key:uid ~data:(ev :: event_list) acc
+          | _ -> acc (* Ignore non-event components *))
+    in
+
+    (* Now revert all the lists *)
+    let events_map = Map.map ~f:List.rev events_map in
+
+    (* let () = *)
+    (*   Map.iter *)
+    (*     ~f:(fun ~key ~data -> *)
+    (*       let uid = key in *)
+    (*       let evs = data in *)
+    (*       Printf.printf "󰧓 ⇒ UID: %s\n" uid; *)
+    (*       List.iter (fun ev -> Printf.printf "%s\n" (Icalendar.show_component (`Event ev))) evs; *)
+    (*       Printf.printf "\n\n") *)
+    (*     events_map *)
+    (* in *)
+    Printf.printf "Events: %d\n\n" (Map.cardinal events_map);
     let events =
       List.filter_map
         (function
@@ -27,8 +48,10 @@ let ical2rem ical_file =
           | _ -> None)
         components
     in
+
     let _reminders = List.map EventTransformer.remind_of_event events in
+
     ()
-  end
+    end
 
 let () = if !Sys.interactive then () else exit (CommandLine.main ical2rem)