Restore ceiling plane in texture experiment

[sabino]

Summary

• re-enable the ceiling perspective plane for the texture_columns experiment
• match the ceiling and floor at two forward-motion phases
• refresh all 20 backdrop columns per frame in the experiment so plane motion tracks wall motion more tightly
• omit title picture C-ROM tiles for this skip-intro experiment to keep live sprites and plane tiles inside the 1 MiB visible C-ROM budget
• use a focused simple-map sprite set and extend the enemy visibility probe to cover both simple-map enemies

Local checks

• python3 -m py_compile tools/*.py
• make experiment-probes EXPERIMENT=texture_columns DOOM_IWAD=/home/sabino/Downloads/Doom1.WAD
• make experiment-cart EXPERIMENT=texture_columns DOOM_IWAD=/home/sabino/Downloads/Doom1.WAD
• git diff --check