Preserved verbatim from the interrupted session. NOTE: build_sail_post_corroded
still carries the M1 mutation (clean galvanised steel, DROOP=0), so the two GLBs
in this commit are the UNTELLED post, not the shipped asset. Restored in the
next commit after the red-check is witnessed.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>