The world renderer drew nothing; make it draw the world

[CaYatur]

The world renderer drew nothing; make it draw the world

#119 shipped a world renderer that produced no output at all on a real world,
and every test was green because none of them read a real chunk.

The palette was unwrapped once and needed twice. prismarine-nbt represents
an NBT list as {type:'list', value:{type:'compound', value:[...]}} — the outer
wrapper says "list", the inner says what the elements are. sections happened
to work because that code unwrapped twice; palette did not, so
Array.isArray(palette) was false for every section of every chunk, every
section was skipped, and every tile came back null. Silently: no error, no
exception, just a map with nothing on it.

Verified against a real Paper 1.21.6 world rather than argued about — 339 chunks
of one region decoded, rendered to an image and looked at. The bit-level work
from #119 turned out to be right: DataVersion 4435, padded packing, and the
long counts match bitsPerIndex exactly (a 26-entry palette is 5 bits and 342
longs, which is what the file holds).

And then it looked wrong, so this fixes that too. The topmost block of a
column is usually the plant standing on the ground rather than the ground: on
that world the commonest surface blocks after grass were short_grass, vine,
fern and bamboo, none of them in the colour table, all falling through to
the stable-hash fallback. A bamboo jungle rendered as a maroon smear and every
meadow as blue-grey.

A map looks through foliage. seeThrough skips grass, ferns, vines, flowers,
bamboo, crops, carpets, signs and the rest — by name and by suffix family, so a
flower added in a future version needs no release — while leaves stay, because a
forest canopy is exactly what you see from above. After it, every drawn surface
block is one the table names.

The common colours are Minecraft's own map-item palette now instead of eyeballed
values, since that is the palette a player recognises. Mine were darker and
redder, which is the other half of why podzol read as maroon.

Asserted with a real NBT chunk built in the test and read by the real function:
air above and stone below renders as stone at the right height, grass with
short_grass on it renders as grass, and an all-air chunk produces no tile.
Proved failable — restoring the single unwrap gives
FAIL - a valid chunk produced no tile — the reader found no sections, which is
precisely what was shipping.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.