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

lib/controllers/author.dart

@@ -0,0 +1,30 @@
+import "dart:async";
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:nexus/controllers/user.dart";
+import "package:nexus/models/content/membership.dart";
+import "package:nexus/models/event.dart";
+
+class AuthorController extends AsyncNotifier<MembershipContent> {
+  final Event event;
+  AuthorController(this.event);
+
+  @override
+  Future<MembershipContent> build() async {
+    final member = await ref.watch(
+      UserController.provider(
+        .new(roomId: event.roomId, userId: event.sender),
+      ).future,
+    );
+
+    return .new(
+      status: member.status,
+      avatarUrl: event.pmp?.avatarUrl ?? member.avatarUrl,
+      displayName: event.pmp?.displayName ?? member.displayName,
+    );
+  }
+
+  static final provider =
+      AsyncNotifierProvider.family<AuthorController, MembershipContent, Event>(
+        AuthorController.new,
+      );
+}