-featureless derives a world datapack from the server jar (inner server
or bundler layout): every biome keeps its carvers but loses its feature
stages and every structure set loses its structures, so the capture is
pure noise terrain with surface rules, carvers, aquifers, and veins.
-blocks-only writes a blocks-only RIOBASE1 fixture for it. -port avoids
colliding with something else already listening on 25565.
CLAUDE.md still claimed there was no placed/configured feature system and
that ores never generate below y=0; both stopped being true when the
stage-6 region replay landed. Document what the replay covers, which
decoration stays hand-written, the measured parity baseline, and the new
env-gated base-terrain diagnostic. README gains the same correction plus
the 966-cell base-terrain measurement.
Splits fixture mismatches into classes that name the responsible
subsystem: plain-vs-plain cells are direct base-terrain defects and come
with sample coordinates, single-side feature states count as flips per
family, and disk-shaped outputs land in an ambiguous bucket so they
cannot pollute the plain signal.
First run on seed 12345: 966 base cells (0.246%), dominated by vanilla-
carved cave segments missing from our carver output and deepslate-to-
water aquifer edges.
The combined stage-6 pass in placeScheduledUndergroundOresStage already
replays ores, underwater magma, and disks in datapack order; the separate
placeScheduledDisks and placeScheduledUnderwaterMagma passes have no
callers left. Keep the per-position helpers the combined pass and tests
use.
