wifi: add log ring buffer visible from JS + log view in wifi piece
- Add wifi_log() helper that writes to both ac_log (stderr/USB log)
and a 32-entry ring buffer on the ACWifi struct
- Replace ac_log calls in connect/scan/autoconnect/disconnect/reconnect
with wifi_log so all wifi activity is captured in the ring buffer
- Expose wifi.logs array in JS bindings (chronological order)
- Add log view to wifi.mjs (press 'l' to toggle fullscreen log panel)
with color-coded entries: red=errors, green=success, yellow=WPA/DHCP
- Logs also persist to /mnt/ac-native.log for offline diagnosis
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>