ap: parallel 2.4GHz AP (hostapd-2g) on the Linksys WUSB6300v2 dongle

Second radio (wlxd8ec5e2faa8c, RTL8822BU/rtw88), same VanLink SSID+PSK,
ch6 HT20, bridged into br0 next to the 5GHz AP. Runs as its own hostapd
instance + own watchdog so a USB wedge on one radio never darkens the
other; van-ap-watchdog now takes conf path + unit name as args (defaults
unchanged). rtw88.conf disables deep power-save (rtw89 gotcha analog)
and the driver's USB2->3 self-upgrade (USB3 noise in the 2.4GHz band —
note: dongle currently sits in a USB3 port, so it still enumerates
SuperSpeed; move to a USB2 port if 2.4GHz range disappoints).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

ap/hostapd-2g.conf

@@ -0,0 +1,25 @@
+interface=wlxd8ec5e2faa8c
+# Second, independent hostapd instance (hostapd-2g.service) — 2.4GHz band of the same
+# VanLink network, bridged into the same br0 segment as the 5GHz AP and the wired port.
+# Separate process on purpose: a USB wedge on one radio must never take down the other.
+bridge=br0
+# Same ctrl dir as the 5GHz AP — sockets are per-interface, hostapd_cli/watchdog use -i.
+ctrl_interface=/var/run/hostapd
+driver=nl80211
+# Same SSID + PSK as 5GHz: dual-band clients pick a band themselves, 2.4-only IoT
+# devices just join. Rename here (e.g. VanLink-2G) if band pinning is ever needed.
+ssid=VanLink
+country_code=CA
+ieee80211d=1
+hw_mode=g
+channel=6
+wmm_enabled=1
+# HT20 only — 40MHz in 2.4GHz overlaps most of the band and coexistence would force
+# it back to 20MHz near any neighbor anyway.
+ieee80211n=1
+ht_capab=[LDPC][SHORT-GI-20]
+auth_algs=1
+wpa=2
+wpa_passphrase=1foot11foot11
+wpa_key_mgmt=WPA-PSK
+rsn_pairwise=CCMP