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

lib/models/requests/set_state.dart

@@ -0,0 +1,23 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+import "package:nexus/models/content/content.dart";
+import "package:nexus/models/ms_duration.dart";
+part "set_state.freezed.dart";
+part "set_state.g.dart";
+
+@freezed
+abstract class SetStateRequest with _$SetStateRequest {
+  const factory SetStateRequest({
+    required String roomId,
+    required String type,
+    required String stateKey,
+    required Content content,
+
+    @JsonKey(name: "delay_ms", includeIfNull: false)
+    @MSDuration()
+    @Default(null)
+    Duration? delay,
+  }) = _SetStateRequest;
+
+  factory SetStateRequest.fromJson(Map<String, Object?> json) =>
+      _$SetStateRequestFromJson(json);
+}