v0.6.1: latest iPXE + automatic NIC driver fallback (more devices, zero toggle)

Mirrors the worthwhile device-support wins from iVentoy 1.0.24→1.0.35 onto our
(very different) proxy-DHCP + iPXE-chainload architecture. iVentoy's other
changes are inapplicable (arm64-server / distro-display fixes live in its
injected Linux, which we don't have), niche (iSCSI), or closed-source
(Matrix Boot).

iPXE refreshed (mirrors 1.0.35 "Update iPXE")
- Pin the from-source build to ipxe/ipxe master @ 2026-06-09
  (95ffbf4745553e8a207922389929e1943c0237c0) — newer NIC drivers + EFI fixes.
  The pin also busts the cached ipxe-build Docker layer so the release
  actually recompiles iPXE; build-ipxe.sh now shallow-fetches an exact SHA.

Automatic NIC driver fallback (mirrors 1.0.34 "driver/boot-file mode" — but
no operator toggle, per request)
- New DriverMode {Firmware, Builtin} in core; ClientArch::ipxe_bootfile_mode
  maps each arch to either the firmware-net build (snponly/undionly, default)
  or the all-drivers build (ipxe.efi/ipxe.pxe/ipxe-i386.efi/ipxe-arm64.efi).
- The DHCP proxy serves Firmware by default — byte-for-byte unchanged, so
  hardware that boots today never regresses. A new DriverEscalation state
  machine watches for the tell-tale failure: a MAC re-PXE-boots (fresh
  firmware DISCOVER) without ever completing the iPXE-user-class handoff that
  proves the firmware NIC stack worked. That MAC is automatically escalated to
  iPXE's own NIC drivers, and the choice is sticky after a confirmed handoff
  (debounced for the :67/:4011 same-boot pair, TTL-pruned, capped). It just
  works — no settings, no UI.
- All-drivers binaries fetched per arch (ipxe.pxe + i386/arm64 native EFI;
  x86_64 ipxe.efi already built from source with PNG); ipxe-assets embeds
  *.pxe and logs availability per (arch, mode).

Core principles intact: DHCP-proxy-only, container-first, Rust-focused (the
logic is all Rust; only the iPXE fetch/build stays shell), Windows hard-rules
untouched (this never goes near Windows boot).

Validation: clippy clean; full workspace test suite green (core 99 incl. new
DriverMode tests, dhcp-proxy +4 escalation tests, http-api 31+68, iso-store
61, tftp 6, bin 2); fmt-clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

crates/dhcp-proxy/Cargo.toml

@@ -18,3 +18,4 @@ tracing.workspace = true
 thiserror.workspace = true
 anyhow.workspace = true
 bytes.workspace = true
+parking_lot.workspace = true