add support for jumping to out-of-context events (#95)

Fixes #84.

Reviewed-on: #95

lib/models/requests/get_event_context.dart

@@ -0,0 +1,17 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+
+part "get_event_context.freezed.dart";
+part "get_event_context.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const GetEventContextRequest({
+  required final String roomId,
+  required final String eventId,
+  final int limit = 20,
+}) with _$GetEventContextRequest {
+  Map<String, Object?> toJson() => _$GetEventContextRequestToJson(this);
+
+  factory GetEventContextRequest.fromJson(Map<String, Object?> json) =>
+      _$GetEventContextRequestFromJson(json);
+}

lib/models/requests/get_mentions.dart

@@ -9,7 +9,7 @@ part "get_mentions.g.dart";
 class GetMentionsRequest({
   @EpochDateTimeConverter() required final DateTime maxTimestamp,
   @JsonKey(name: "type") required final UnreadType unreadType,
-  required final int limit,
+  final int limit = 20,
   final String? roomId,
 }) with _$GetMentionsRequest {
   Map<String, Object?> toJson() => _$GetMentionsRequestToJson(this);

lib/models/requests/paginate_manual.dart

@@ -0,0 +1,22 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+import "package:nexus/models/direction.dart";
+
+part "paginate_manual.freezed.dart";
+part "paginate_manual.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const PaginateManualRequest({
+  required final String roomId,
+  // Root event ID of a thread to paginate
+  final String? threadRoot,
+  // Can be null for starting pagination of a thread
+  final String? since,
+  required final Direction direction,
+  final int limit = 20,
+}) with _$PaginateManualRequest {
+  Map<String, Object?> toJson() => _$PaginateManualRequestToJson(this);
+
+  factory PaginateManualRequest.fromJson(Map<String, Object?> json) =>
+      _$PaginateManualRequestFromJson(json);
+}