feat(frontend): incomplete port to next.js

frontend/lib/types.ts

@@ -0,0 +1,55 @@
+export interface MeUser extends User {
+  avatar_source: string | null;
+  discord: string | null;
+  discord_username: string | null;
+}
+
+export interface User {
+  id: string;
+  username: string;
+  display_name: string | null;
+  bio: string | null;
+  avatar_url: string | null;
+  links: string[] | null;
+  members: PartialMember[];
+  fields: Field[];
+}
+
+export interface PartialMember {
+  id: string;
+  name: string;
+  avatar_url: string | null;
+}
+
+export interface Field {
+  name: string;
+  favourite: string[] | null;
+  okay: string[] | null;
+  jokingly: string[] | null;
+  friends_only: string[] | null;
+  avoid: string[] | null;
+}
+
+export interface APIError {
+  code: ErrorCode;
+  message?: string;
+  details?: string;
+}
+
+export enum ErrorCode {
+  BadRequest = 400,
+  Forbidden = 403,
+  InternalServerError = 500,
+
+  InvalidState = 1001,
+  InvalidOAuthCode = 1002,
+  InvalidToken = 1003,
+
+  UserNotFound = 2001,
+}
+
+export interface SignupRequest {
+  username: string;
+  ticket: string;
+  invite_code?: string;
+}