refactor: migrate authentication and signup flow to use external API and improve type safety

lib/backend-types.ts

@@ -0,0 +1,31 @@
+export interface Links {
+	next_page: string | null;
+	previous_page: string | null;
+}
+export interface Meta {
+	total: number;
+	per_page: number;
+	current_page: number;
+	last_page: number;
+}
+
+export interface DataResponse<T> {
+	meta: Meta;
+	links: Links;
+	data: T[];
+}
+
+export interface Atoll {
+	id: number;
+	islands: Island[];
+	name: string;
+	createdAt: string;
+	updatedAt: string;
+}
+
+export interface Island {
+	id: number;
+	name: string;
+	createdAt: string;
+	updatedAt: string;
+}