treewide(refactor): rename files to follow the same style

lib/models/requests/paginate.dart

@@ -0,0 +1,15 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+part "paginate.freezed.dart";
+part "paginate.g.dart";
+
+@freezed
+abstract class PaginateRequest with _$PaginateRequest {
+  const factory PaginateRequest({
+    required String roomId,
+    required int? maxTimelineId,
+    @Default(20) int limit,
+  }) = _PaginateRequest;
+
+  factory PaginateRequest.fromJson(Map<String, Object?> json) =>
+      _$PaginateRequestFromJson(json);
+}