fix(submodule): point .gitmodules at the line the pin is actually on

The wireguard-go submodule is pinned to 7d15f33, which lives on lx-awg2-v005.
.gitmodules named `lx` — a separate line, 42 commits one way and 131 the other,
with no common recent history.

That is a loaded gun rather than a cosmetic mismatch. `lx` has no hasReserved()
gate in conn/bind_std.go at all, so a single `git submodule update --remote`
would move the pin there and silently restore the defect fixed yesterday: the
bind shreds the AmneziaWG magic header of every transport packet, handshakes
complete, no data moves, and no chain containing an AmneziaWG node carries
traffic. It would also drop the padding-overrun fix and the v0.0.5 re-graft.

Nothing about the checked-out tree changes — the pin is untouched. Only the
branch a --remote update would follow.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.gitmodules

@@ -7,4 +7,10 @@
 [submodule "submodules/wireguard-go"]
 	path = submodules/wireguard-go
 	url = https://github.com/Leadaxe/wireguard-go-awg2-lx
-	branch = lx
+	# The pin lives on lx-awg2-v005, NOT on lx: the two are separate lines (42
+	# commits apart one way, 131 the other). `lx` has no hasReserved() gate in
+	# conn/bind_std.go at all, so a `git submodule update --remote` against it
+	# would silently restore the bug where ClientBind/StdNetBind shred the
+	# AmneziaWG magic header and no chain carries traffic. Keep this pointing at
+	# the line the pin is actually on.
+	branch = lx-awg2-v005