feat: add functional authentication

api/routes/auth/session.ts

@@ -0,0 +1,12 @@
+import { UnauthorizedError } from "@spec/relay/mod.ts";
+import { session } from "@spec/schemas/auth/routes.ts";
+
+import { getAccountById } from "~stores/read-store/methods.ts";
+
+export default session.access("session").handle(async ({ accountId }) => {
+  const account = await getAccountById(accountId);
+  if (account === undefined) {
+    return new UnauthorizedError();
+  }
+  return account;
+});