Resolve ai-service directly from the RAG routes, never the gateway

apps/web/app/api/sections/route.ts

@@ -2,11 +2,16 @@ import { NextResponse } from "next/server";
 
 export const runtime = "nodejs";
 
-const API_GATEWAY_URL =
-  process.env.API_GATEWAY_URL ?? process.env.AI_SERVICE_URL ?? "http://localhost:8000";
+// RAG never goes through api-gateway. The gateway proxies `/auth/*` only --
+// apps/api-gateway/src/proxy/ holds a single AuthProxyController -- so
+// preferring AI_SERVICE_URL here pointed every RAG call at a service with no
+// such route the moment apiGateway was enabled, breaking chat, suggest,
+// history, sections, section-text and feedback at once. Resolve ai-service
+// directly and let AI_SERVICE_URL mean what its name says: auth only.
+const AI_SERVICE_URL = process.env.AI_SERVICE_URL ?? "http://localhost:8000";
 
 function ragBaseUrl() {
-  return API_GATEWAY_URL.replace(/\/v1\/rag(?:\/query)?\/?$/, "");
+  return AI_SERVICE_URL.replace(/\/v1\/rag(?:\/query)?\/?$/, "");
 }
 
 export async function GET(request: Request) {