Add Samsung soundbar and mDNS repeater (VLAN 10<->30); note casting firewall drift

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/11-CROSS-VLAN-CASTING.md

@@ -165,3 +165,13 @@ If your Mac is connected to WireGuard VPN, the VPN overrides the default route
 ### CAP VLAN Limit
 
 The CAP XL ac may show "maximum VLAN count for interface was reached." If a device can't connect to WiFi, try disabling the CAP interfaces temporarily to force connection to the HAP's radio directly.
+
+## Update 2026-10-10 — Samsung soundbar + mDNS repeater
+
+| Device | MAC (WiFi) | IP | VLAN |
+|--------|-----------|----|------|
+| Samsung HW-Q990H soundbar (Chromecast built-in, "Q-Series Soundbar") | 80:0D:3F:5F:FC:C8 | 192.168.30.118 (dynamic lease) | 30 |
+
+- **mDNS repeater enabled:** `/ip dns set mdns-repeat-ifaces=vlan10-mgmt,vlan30-iot` (RouterOS 7.24.5, hAP ax³). Lets Home Assistant / Music Assistant on HAOS (`192.168.10.102`) discover Cast devices on IoT.
+- Soundbar is in Home Assistant via the Google Cast integration (`known_hosts: 192.168.30.118`).
+- **Drift note:** the live router has **no** `casting-devices` address list and **no** IoT→Mgmt/Trusted drop rules (19 filter rules total, checked 2026-10-10). Sections 1–2 above describe an earlier ruleset; inter-VLAN unicast is currently open.

docs/CHANGELOG.md

@@ -567,3 +567,7 @@ Categories:
 - [VLAN] - VLAN configuration changes
 - [DOCKER] - Docker maintenance
 ```
+
+## 2026-10-10
+- MikroTik: enabled mDNS repeater between vlan10-mgmt and vlan30-iot (Music Assistant / Cast discovery for the Samsung HW-Q990H soundbar).
+- HAOS: Core 2026.10.0, OS 18.3; Music Assistant add-on 2.10.6 installed; soundbar added via Google Cast.