Keep verified Gateway active through transient discovery failures

test/server/gateway-presence.test.js

@@ -78,7 +78,7 @@ test('Gateway presence is authenticated by the shared subscription secret', asyn
   }), false);
 });
 
-test('host route freshness and Gateway failures drive a safe automatic fallback', () => {
+test('verified Gateway stays active through transient discovery failures', () => {
   const now = Date.now();
   const statePath = path.join(fs.mkdtempSync(path.join(os.tmpdir(), 'harbor-route-')), 'network.json');
   fs.writeFileSync(statePath, JSON.stringify({
@@ -106,14 +106,23 @@ test('host route freshness and Gateway failures drive a safe automatic fallback'
   state = nextGatewayAutoState(state, { network });
   assert.equal(state.mode, 'gateway-direct');
   state = nextGatewayAutoState(state, { network });
-  assert.equal(state.mode, 'local-vpn');
+  assert.equal(state.mode, 'gateway-direct');
+  assert.equal(state.gatewayId, 'gateway-1');
+  assert.equal(state.failures, 3);
+
+  state = nextGatewayAutoState(state, {
+    network: null,
+    error: 'host snapshot stale',
+  });
+  assert.equal(state.mode, 'gateway-direct');
+  assert.equal(state.gatewayId, 'gateway-1');
+  assert.equal(state.lastError, 'host snapshot stale');
+  assert.equal(applyGatewayPreference(state, false).mode, 'local-vpn');
 
   const newNetwork = { ...network, mac: '11:22:33:44:55:66' };
-  state = nextGatewayAutoState(nextGatewayAutoState(createGatewayAutoState(), {
-    network,
-    verifiedGateway: { gatewayId: 'gateway-1' },
-  }), { network: newNetwork });
+  state = nextGatewayAutoState(state, { network: newNetwork });
   assert.equal(state.mode, 'local-vpn');
+  assert.equal(state.gatewayId, '');
 
   assert.equal(readHostNetworkState(statePath, { now: now + 16_000 }), null);