wg_handshake: log wireguard handshake message

Signed-off-by: Vincent Li <vincent.mc.li@gmail.com>

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# Date:      Fri Nov 7 19:17:59 2025 -0800
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# interactive rebase in progress; onto 4fa5ddf
# Last commands done (2 commands done):
#    pick 6424fa8 wg_handshake: log wireguard handshake message
#    squash ac8084d rename
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# You are currently rebasing branch 'loongfire-port' on '4fa5ddf'.
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# Changes to be committed:
#	modified:   examples/c/Makefile
#	new file:   examples/c/wg_handshake.bpf.c
#	new file:   examples/c/wg_handshake.c
#	new file:   examples/c/wg_handshake.h
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# Untracked files:
#	examples/c/biotop
#	examples/c/cscope.out
#	examples/c/fentry.bpf.c.2
#	examples/c/fentry.bpf.c.4
#	examples/c/fentry.bpf.c.5
#	examples/c/fentry.bpf.c.orig
#	examples/c/fentry.bpf.c.poke
#	examples/c/netqtop
#	examples/c/network_helpers.h
#	examples/c/page_pool_modify.bpf.c
#	examples/c/page_pool_modify.c
#	examples/c/page_pool_stats.bpf.c
#	examples/c/page_pool_stats.c
#	examples/c/page_pool_stats.h
#	examples/c/stackcount.bpf.c
#	examples/c/stackcount.c
#	examples/c/stackcount.h
#	examples/c/stmmac_bpf_trace.bpf.c
#	examples/c/stmmac_bpf_trace.bpf.c.orig
#	examples/c/stmmac_bpf_trace.c
#	examples/c/stmmac_bpf_trace.h
#	examples/c/tc_syncookie
#	examples/c/tc_syncookie.c.orig
#	examples/c/tcpstates
#	examples/c/wg_handshake
#
