fix(gateway): skip Control UI pairing when auth.mode=none (closes #42931) (#47148)

When auth is completely disabled (mode=none), requiring device pairing
for Control UI operator sessions adds friction without security value
since any client can already connect without credentials.

Add authMode parameter to shouldSkipControlUiPairing so the bypass
fires only for Control UI + operator role + auth.mode=none. This avoids
the #43478 regression where a top-level OR disabled pairing for ALL
websocket clients.

src/gateway/server/ws-connection/connect-policy.test.ts

@@ -226,6 +226,30 @@ describe("ws connect policy", () => {
     expect(shouldSkipControlUiPairing(strict, "operator", true)).toBe(true);
   });
 
+  test("auth.mode=none skips pairing for operator control-ui only", () => {
+    const controlUi = resolveControlUiAuthPolicy({
+      isControlUi: true,
+      controlUiConfig: undefined,
+      deviceRaw: null,
+    });
+    const nonControlUi = resolveControlUiAuthPolicy({
+      isControlUi: false,
+      controlUiConfig: undefined,
+      deviceRaw: null,
+    });
+    // Control UI + operator + auth.mode=none: skip pairing (the fix for #42931)
+    expect(shouldSkipControlUiPairing(controlUi, "operator", false, "none")).toBe(true);
+    // Control UI + node role + auth.mode=none: still require pairing
+    expect(shouldSkipControlUiPairing(controlUi, "node", false, "none")).toBe(false);
+    // Non-Control-UI + operator + auth.mode=none: still require pairing
+    // (prevents #43478 regression where ALL clients bypassed pairing)
+    expect(shouldSkipControlUiPairing(nonControlUi, "operator", false, "none")).toBe(false);
+    // Control UI + operator + auth.mode=shared-key: no change
+    expect(shouldSkipControlUiPairing(controlUi, "operator", false, "shared-key")).toBe(false);
+    // Control UI + operator + no authMode: no change
+    expect(shouldSkipControlUiPairing(controlUi, "operator", false)).toBe(false);
+  });
+
   test("trusted-proxy control-ui bypass only applies to operator + trusted-proxy auth", () => {
     const cases: Array<{
       role: "operator" | "node";

src/gateway/server/ws-connection/connect-policy.ts

@@ -3,6 +3,7 @@ import type { GatewayRole } from "../../role-policy.js";
 import { roleCanSkipDeviceIdentity } from "../../role-policy.js";
 
 export type ControlUiAuthPolicy = {
+  isControlUi: boolean;
   allowInsecureAuthConfigured: boolean;
   dangerouslyDisableDeviceAuth: boolean;
   allowBypass: boolean;
@@ -24,6 +25,7 @@ export function resolveControlUiAuthPolicy(params: {
   const dangerouslyDisableDeviceAuth =
     params.isControlUi && params.controlUiConfig?.dangerouslyDisableDeviceAuth === true;
   return {
+    isControlUi: params.isControlUi,
     allowInsecureAuthConfigured,
     dangerouslyDisableDeviceAuth,
     // `allowInsecureAuth` must not bypass secure-context/device-auth requirements.
@@ -36,10 +38,21 @@ export function shouldSkipControlUiPairing(
   policy: ControlUiAuthPolicy,
   role: GatewayRole,
   trustedProxyAuthOk = false,
+  authMode?: string,
 ): boolean {
   if (trustedProxyAuthOk) {
     return true;
   }
+  // When auth is completely disabled (mode=none), there is no shared secret
+  // or token to gate pairing. Requiring pairing in this configuration adds
+  // friction without security value since any client can already connect
+  // without credentials. Guard with policy.isControlUi because this function
+  // is called for ALL clients (not just Control UI) at the call site.
+  // Scope to operator role so node-role sessions still need device identity
+  // (#43478 was reverted for skipping ALL clients).
+  if (policy.isControlUi && role === "operator" && authMode === "none") {
+    return true;
+  }
   // dangerouslyDisableDeviceAuth is the break-glass path for Control UI
   // operators. Keep pairing aligned with the missing-device bypass, including
   // open-auth deployments where there is no shared token/password to prove.

src/gateway/server/ws-connection/message-handler.ts

@@ -681,7 +681,13 @@ export function attachGatewayWsMessageHandler(params: {
             hasBrowserOriginHeader,
             sharedAuthOk,
             authMethod,
-          }) || shouldSkipControlUiPairing(controlUiAuthPolicy, role, trustedProxyAuthOk);
+          }) ||
+          shouldSkipControlUiPairing(
+            controlUiAuthPolicy,
+            role,
+            trustedProxyAuthOk,
+            resolvedAuth.mode,
+          );
         if (device && devicePublicKey && !skipPairing) {
           const formatAuditList = (items: string[] | undefined): string => {
             if (!items || items.length === 0) {