feat: Implement oauth service and client registration

src/api/client/oauth/mod.rs

@@ -0,0 +1,17 @@
+mod register_client;
+mod server_metadata;
+
+use axum::{
+	Json, Router,
+	routing::method_routing::{get, post},
+};
+use serde_json::json;
+pub(crate) use server_metadata::*;
+
+pub(crate) const BASE_PATH: &str = "/_continuwuity/oauth2/";
+
+pub(crate) fn router() -> Router<crate::State> {
+	Router::new()
+		.route("/client/register", post(register_client::register_client_route))
+		.route("/client/keys.json", get(async || Json(json!({"keys": []}))))
+}