fix(zigbee): preserve the device tooltip discriminator

Full release CI caught room becoming undefined instead of false after the
pointer-tooltip path stopped calling _showTip. Preserve the existing shape;
keep and strengthen the room-tooltip-toggle regression assertion.

Issue: #802
User-Visible: no

demo/smoke_room_tooltip_toggle.mjs

@@ -129,7 +129,9 @@ const result = await page.evaluate(async () => {
 
   root().querySelector('.dev').dispatchEvent(mouse('pointermove', 200, 200));
   await card.updateComplete;
-  out.deviceTipSurvives = card._tip?.room === false && !!root().querySelector('.tip');
+  const deviceTip = root().querySelector('.tip');
+  out.deviceTipSurvives = card._tip?.room === false && !!deviceTip && !deviceTip.hidden
+    && deviceTip.textContent.includes(card._tip.title);
 
   card._openSettingsDialog();
   out.reopenShowsOff = card._settingsDialog?.showRoomTooltip === false;

src/live-hover.ts

@@ -71,7 +71,7 @@ export function showDevicePointerTip(value: object, event: PointerEvent, device:
   }
   const tip = deviceTipContent(host, device);
   host._deviceHits.hover(host.renderRoot, device.id);
-  host._tip = { x: event.clientX, y: event.clientY, ...tip, source: 'pointer', deviceId: device.id };
+  host._tip = { x: event.clientX, y: event.clientY, ...tip, room: false, source: 'pointer', deviceId: device.id };
   syncHouseplanHover(host);
 }