Bed: replace procedural draw with 1×2 vertical bundle sprite

The procedural 3/4-perspective bed (16×16 box of stacked draw_rect calls)
gets replaced with a 16×32 single-column Sprite2D cropped from the ElvGames
House Interior tileset. The sprite spans the bed's tile plus the tile
immediately south — head with rounded pillow + frame in the bed tile, body
and wood foot rail in the foot tile. The foot tile stays walkable in the
pathfinder (Phase-4 simplification, matches small rocks).

Three variants chosen deterministically by tile hash so the same bed renders
the same colour across boots and saves:
  • (32, 22) brown wood frame
  • (35, 22) blue quilt
  • (38, 22) pink quilt
Crops are LEFT-edge columns of the 2-/3-wide bundle beds — visually verified
in /tmp/bed_candidates.png against MIDDLE/RIGHT alternatives. LEFT shows the
clearest pillow shape + visible wood frame in a single column.

Setup work (sprite, position, y-sort) now lives inside setup() not _ready()
because _ready fires inside add_child() before the caller passes in the real
tile — same lesson as BigRock. _build_sprite() is idempotent (drops the
previous Sprite child) so the save-load flow (factory.setup → factory
on_build_tick → from_dict.setup) re-creates the sprite without leaks.

_draw() now renders only the medical-cross overlay when is_medical is true
— sprite handles ghost alpha via modulate. _complete() solidifies the sprite
from 0.4 to 1.0 alpha. The quality-tinted procedural sheets are dropped;
quality still drives sleep mood, just not visual colour.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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