feat: implement friends API with routes to get friends list and update thought visibility logic

thoughts-backend/doc/src/friends.rs

@@ -0,0 +1,12 @@
+use utoipa::OpenApi;
+
+use api::models::{ApiErrorResponse, ParamsErrorResponse};
+use api::routers::friends::*;
+use models::schemas::user::{UserListSchema, UserSchema};
+
+#[derive(OpenApi)]
+#[openapi(
+    paths(get_friends_list,),
+    components(schemas(UserListSchema, ApiErrorResponse, ParamsErrorResponse, UserSchema))
+)]
+pub(super) struct FriendsApi;