Give the event banners a top-down night gradient so they read as lit cloth

docs/assets/3d-model-review.md

@@ -334,7 +334,21 @@ and energy:
 Mean luminance 0–255. The shipped values brighten the pool past the old setting while darkening the
 gap between poles, which is what "pools, not a wash" means numerically.
 
-Still open from the milestone: marquee emissive under Compatibility.
+### Event banners read as lit cloth (2026-11-06)
+
+The banners were one flat emissive panel, so they measured the same luminance from the mounting bar
+to the hem (114/121/122/125 down the panel) and read as a painted red card rather than lit fabric.
+They are now four stacked strips with a night gradient (energies 2.6 / 2.2 / 1.8 / 1.4), carried per
+material through `night_energy` metadata so `set_night_mode` keeps the ratio instead of flattening it.
+
+| | Before | After |
+| --- | --- | --- |
+| Vertical profile down a banner | 114 → 125 (flat) | 135 → 84 |
+| Clipping (p99 / pixels ≥ 250) | 192 / 0.2 % | 192 / 0.2 % |
+| Daylight read | uniform | uniform (strips flush, no seam) |
+
+No clipping in either state, and the Compatibility renderer draws it with the same flat emissive
+material as before — the change is geometry plus per-material energy, not a new shader.
 
 ## Scorecard skeleton