HOW IT WORKS
One device creates a Show ID, everyone else enters the same ID. Cue list and state syncs live across all browsers — Chrome, Safari, anything.

QLAB INTEGRATION (QLab operator's machine)
Add a Network Cue after any cue in QLab. Set type to HTTP POST, URL:
https://cueview-2bbc7-default-rtdb.firebaseio.com/shows/YOUR-SHOW-ID/qlabTrigger.json

Body (raw JSON): {"code":"Q01","ts":0}

Replace YOUR-SHOW-ID with the Show ID above, Q01 with the QLab Code you typed on the DSM cue. Only cues that have a matching QLab Code in the list will react — all others are ignored.

SECURITY RULES — paste these into Firebase Console → Realtime Database → Rules:

{
  "rules": {
    "shows": {
      "$showId": {
        ".read": true,
        ".write": true,
        "state": { ".validate": "newData.hasChildren(['cues','currentIdx','ts'])" },
        "qlabTrigger": { ".validate": "newData.hasChildren(['code','ts'])" }
      }
    }
  }
}