fix(auth): declare local development environment

backend/test/config.test.ts

@@ -1,5 +1,5 @@
 import { expect, test } from "vitest";
-import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { stringify } from "yaml";
@@ -88,6 +88,12 @@ test("loadConfig allows none and mock only outside production when auth.yaml is
     .toThrow("production requires auth.yaml or AUTH_MODE=upstream");
 });
 
+test("local Compose profiles explicitly select the development auth environment", () => {
+  for (const profile of ["../../deploy/compose.local.yaml", "../../docker-compose.dev.yml"]) {
+    expect(readFileSync(new URL(profile, import.meta.url), "utf8")).toMatch(/NODE_ENV:\s*development/);
+  }
+});
+
 test("loadConfig makes an existing auth.yaml authoritative and rejects AUTH_MODE split-brain", () => {
   const { directory, file } = authFile(oidcAuthConfig());
   try {