[www] flag to disable websignups

apps/www/vitest.config.ts

@@ -24,6 +24,9 @@ export default defineConfig({
 				},
 				bindings: {
 					ENVIRONMENT: 'VITEST',
+					// Web signup is OFF unless the operator switches it on; the signup tests below
+					// exercise the open door, and one flips this off to pin the closed one.
+					PASSWORD_SIGNUP: 'on',
 					// The Turnstile keypair is NOT bound here: both keys come from the Secrets
 					// Store now, and the tests seed the local store with the test pair (see
 					// src/test/integration/api.test.ts). A plain binding of the same name would