Move the external API into its own router

Auth logic isn't shared between the clients anyway, so co-locating them is confusing since you can't use the same clients to call both. This also makes the codegen clients less verbose.

app/src/pages/api/v1/openapi.json.ts

@@ -0,0 +1,16 @@
+import { type NextApiRequest, type NextApiResponse } from "next";
+import { generateOpenApiDocument } from "trpc-openapi";
+import { v1ApiRouter } from "~/server/api/external/v1Api.router";
+
+export const openApiDocument = generateOpenApiDocument(v1ApiRouter, {
+  title: "OpenPipe API",
+  description: "The public API for reporting API calls to OpenPipe",
+  version: "0.1.1",
+  baseUrl: "https://app.openpipe.ai/api/v1",
+});
+// Respond with our OpenAPI schema
+const hander = (req: NextApiRequest, res: NextApiResponse) => {
+  res.status(200).send(openApiDocument);
+};
+
+export default hander;