Prefix Zabbix visible name with QRS-

Zabbix host visible name is now "QRS-<yodeck_name>" (e.g. QRS-AMS-COF1).
Existing hosts will be renamed on the next Yodeck poll.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/zabbix.py

@@ -3,7 +3,7 @@ Zabbix API client for automatic host management.
 
 Each Yodeck player becomes a Zabbix host with:
   - hostname  : yodeck#<yodeck_id>
-  - visible name: the Yodeck player's display name
+  - visible name: "QRS-" + the Yodeck player's display name (e.g. QRS-AMS-COF1)
   - SNMP v2c interface pointing to this app (APP_HOST:161)
   - Four SNMP items: online, last_seen, updating, registered
 """
@@ -152,7 +152,7 @@ def sync_to_zabbix(players, add_log_fn):
         for player in players:
             yid      = player['id']
             hostname = f"yodeck#{yid}"
-            visible  = player['name']
+            visible  = f"QRS-{player['name']}"
 
             if hostname not in existing:
                 hostid = zbx.create_host(hostname, visible, groupid)