Fix pickup floor seating

[sabino]

Summary

• Removes the extra height-dependent pickup lift so floor items use the baked bottom-origin anchor and sit closer to the floor perspective line.
• Updates the powerup screenshot checker crop bands to the new lower-seated pickup positions.
• Adds before/after evidence from the default simple showcase route.

Visual Evidence

Before	After

Side-by-side committed at docs/screenshots/item-ground-before-after.png.

Validation

• make cart DOOM_IWAD=/home/sabino/Downloads/Doom1.WAD BUILDDIR=build/item-ground-fix ROM=build/item-ground-fix-rom GFX_ROM_DIR=build/item-ground-fix-assets
• Routed Xvfb captures:
  • .tools/screens/latest/item-row-before.png
  • .tools/screens/latest/item-row-after.png
• git diff --check
• make key-test-rom DOOM_IWAD=/home/sabino/Downloads/Doom1.WAD
• make powerup-test-rom DOOM_IWAD=/home/sabino/Downloads/Doom1.WAD
• python3 -m py_compile tools/check_powerup_screens.py
• SMOKE_XVFB=1 SMOKE_OUTPUT_DIR=.tools/screens/latest/item-ground-powerup-smoke DOOM_IWAD=/home/sabino/Downloads/Doom1.WAD tools/smoke_powerup.sh

Notes

This does not change pickup scaling or the wall/simple-map renderer. It only changes pickup vertical anchoring so the shrink/readability fix no longer reads as floating above the floor.

[sabino]

Screenshot evidence for the pickup ground-seating fix:

Before	After

The after capture uses the same simple-showcase route and camera timing as the before capture. The pickup scale is unchanged; only the pickup floor anchor is lower/seated against the floor perspective.

[sabino]

Follow-up after live testing:

• Added a far-distance-only downward bias for pickup floor seating so tiny distant items no longer read as floating.
• Fixed the hurt checker overlay cleanup path so the red damage flash still appears when hit, but cannot stay stuck after hurt_flash ends.

Latest live capture after the far-item bias:

Additional validation after the follow-up:

• git diff --check
• make cart DOOM_IWAD=/home/sabino/Downloads/Doom1.WAD BUILDDIR=build/item-ground-fix ROM=build/item-ground-fix-rom GFX_ROM_DIR=build/item-ground-fix-assets
• SMOKE_XVFB=1 SMOKE_OUTPUT_DIR=.tools/screens/latest/item-ground-powerup-smoke DOOM_IWAD=/home/sabino/Downloads/Doom1.WAD tools/smoke_powerup.sh