fix(webapp): keep the V1 rejection on the queues API routes

The dashboard-side cleanup dropped the engine-version failure arm from the
queue presenters, which also removed the 400 that GET /api/v1/queues and
GET /api/v1/queues/:queueParam returned for engine V1 projects. Restore that
rejection in the two API route handlers so v3 clients still get a clean 4xx,
while the dashboard keeps the simplified presenter result and page.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: claude

apps/webapp/app/routes/api.v1.queues.$queueParam.ts

@@ -3,6 +3,7 @@ import { type QueueItem, type RetrieveQueueParam, RetrieveQueueType } from "@tri
 import { z } from "zod";
 import { QueueRetrievePresenter } from "~/presenters/v3/QueueRetrievePresenter.server";
 import { createLoaderApiRoute } from "~/services/routeBuilders/apiBuilder.server";
+import { determineEngineVersion } from "~/v3/engineVersion.server";
 
 const SearchParamsSchema = z.object({
   type: RetrieveQueueType.default("id"),
@@ -24,6 +25,15 @@ export const loader = createLoaderApiRoute(
     },
   },
   async ({ params, searchParams, authentication }) => {
+    // v3 (engine V1) has no V2 queues to retrieve, so old clients get a clean 400.
+    const engineVersion = await determineEngineVersion({
+      environment: authentication.environment,
+    });
+
+    if (engineVersion === "V1") {
+      return json({ error: "engine-version" }, { status: 400 });
+    }
+
     const input: RetrieveQueueParam =
       searchParams.type === "id"
         ? params.queueParam

apps/webapp/app/routes/api.v1.queues.ts

@@ -8,6 +8,7 @@ import {
 import { toOffsetLimitQueueListPagination } from "~/presenters/v3/queueListPagination.server";
 import { logger } from "~/services/logger.server";
 import { createLoaderApiRoute } from "~/services/routeBuilders/apiBuilder.server";
+import { determineEngineVersion } from "~/v3/engineVersion.server";
 import { ServiceValidationError } from "~/v3/services/baseService.server";
 
 const SearchParamsSchema = z.object({
@@ -30,6 +31,15 @@ export const loader = createLoaderApiRoute(
     const service = new QueueListPresenter(searchParams.perPage);
 
     try {
+      // v3 (engine V1) has no V2 queues to list, so old clients get a clean 400.
+      const engineVersion = await determineEngineVersion({
+        environment: authentication.environment,
+      });
+
+      if (engineVersion === "V1") {
+        return json({ error: "engine-version" }, { status: 400 });
+      }
+
       const result = await service.call({
         environment: authentication.environment,
         page: searchParams.page ?? 1,