feat(api): expose REST-only agent routes

src/routes/publicApi.ts

@@ -0,0 +1,55 @@
+import { randomUUID } from "node:crypto";
+import { type Request, type Response, Router } from "express";
+
+const problemDetails = (req: Request, status: number, body: unknown) => {
+  const record =
+    typeof body === "object" && body !== null
+      ? (body as Record<string, unknown>)
+      : {};
+  const detail =
+    typeof record.detail === "string"
+      ? record.detail
+      : typeof record.message === "string"
+        ? record.message
+        : `Request failed with status ${status}`;
+  const codeByStatus: Record<number, string> = {
+    400: "invalid_request",
+    401: "unauthenticated",
+    403: "forbidden",
+    404: "not_found",
+    409: "conflict",
+    422: "validation_error",
+    503: "dependency_unavailable",
+  };
+  const code = codeByStatus[status] ?? "request_error";
+  return {
+    type: `https://tjwater.example/problems/${code.replaceAll("_", "-")}`,
+    title: code.replaceAll("_", " "),
+    status,
+    detail,
+    instance: req.originalUrl.split("?")[0],
+    code,
+    trace_id: req.header("x-request-id") ?? randomUUID(),
+    errors: record.detail && typeof record.detail === "object" ? [record.detail] : [],
+  };
+};
+
+export const buildAgentPublicRouter = (chatRouter: Router) => {
+  const router = Router();
+
+  router.use((req, res, next) => {
+    const json = res.json.bind(res);
+    res.json = ((body: unknown) => {
+      if (res.statusCode >= 400) {
+        res.type("application/problem+json");
+        return json(problemDetails(req, res.statusCode, body));
+      }
+      return json(body);
+    }) as Response["json"];
+    next();
+  });
+
+  router.use(chatRouter);
+
+  return router;
+};