v0.2.1 — faster throughput, smoother background scans

Fixes the throughput cap and reduces latency spikes during background scans.
It is still experimental and has been tested on one machine only (Lenovo Legion
Slim 5 16APH8, RZ616, macOS 26.7.1). The Sequoia build is compiled from the
same source but was not retested on macOS 15.

• AirportMtkWlan-Sequoia-v0.2.1.zip: native Wi-Fi menu, macOS 15 Sequoia.
• AirportMtkWlan-Tahoe-v0.2.1.zip: native Wi-Fi menu, macOS 26 Tahoe.
• SimpleMtkWlan-v0.2.1.zip: Ethernet-style; join with mtkctl.
• mtkctl-v0.2.1.zip: command-line client for both kexts.

Both AirportMtkWlan zips contain a kext named AirportMtkWlan.kext. Use the one
for your macOS version: a Sequoia build loads on Tahoe but never attaches. Load
one kext only.

Changes since v0.2.0

• Much lower CPU use per packet. The MT7922 can only DMA below 4 GB, so on
  machines with more RAM almost every packet is copied through a bounce
  buffer, and those buffers were uncached. On the test network, download went
  from 41 to 96 Mbit/s and upload from 36 to 100 Mbit/s, with kernel_task
  dropping from about 97% to about 40%.
• Shorter background-scan dwell. The per-channel dwell now follows the
  off-channel time macOS asks for (one third of it, since the firmware visits
  about three channels per trip). Worst-case ping during a scan went from about
  300 ms to about 140 ms. mtkctl dwell <ms|auto> overrides it.
• macOS now sees the real TX rate (for example 867 Mbit/s, MCS 9) instead of a
  fixed low value. It is taken from firmware TX status reports, which are now
  requested only a few times per second instead of for every frame.
• On firmware beacon loss the driver probes the AP before dropping the link.
• BSS_ABSENCE firmware events are ignored quietly.
• When the firmware stops DMA, the driver logs the TX descriptor it rejected,
  to help track down the cause.

Known problems

• Throughput above about 100 Mbit/s has not been measured yet.
• macOS link-quality reports still carry no RSSI.
• Sleep/wake is not tested. No WPA3-only (SAE), no 802.11ax, no 6 GHz.

For installation and troubleshooting, see the README.

Built from 9eff544 (Debug, x86_64, unsigned). Checksums are in SHA256SUMS.txt.