The Pico W now connects end to end with NO backend: status reaches
CYW43_LINK_UP (3) and network.WLAN().isconnected() returns True.
After association the STA's lwIP broadcasts DHCP DISCOVER and ARPs the
gateway over the cyw43 DATA channel. A self-contained virtual network
(new virtualNet.ts) answers them:
- DHCP DISCOVER -> OFFER, REQUEST -> ACK (Ethernet+IPv4+UDP+BOOTP, valid
IPv4 header checksum, UDP checksum 0), leasing 192.168.4.2 with gateway
192.168.4.1.
- ARP who-has the gateway -> is-at the AP MAC.
On by default (Cyw43EmulatorOptions.virtualNet); pass null when an
external packet bridge owns the network.
Also fixes injectPacket to prepend the 4-byte BDC header that chip->host
DATA frames need (same as the event-frame fix), so injected packets parse.
Boot harness now reports: STEP_CONNECT_CALLED status=3 / POLL 0 status 3
conn True / HARNESS_DONE.
Known: receiving packets triggers ~30 rp2040js unaligned-read warnings
(lwIP reads the IPv4 header at ethernet offset 14); non-fatal here, but
the production RP2040Simulator must use a non-throwing logger.
David Montero