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

MEMORY.md

@@ -130,6 +130,10 @@ canonical implemented-features list in `docs/project/development-status.md`.
   gear library. The procedural library + MakeHuman head stay in the tree as the tested fallback
   (`build --source procedural`), not in the shipped roster. Silhouette variety is the known
   regression — three meshes for twelve roles — and the modular part library is the `0.9.10` fix.
+- **Emissive materials can carry a per-material night energy.** `set_night_mode` used to write one
+  multiplier into every `_marquee_emissive` entry, which flattens any gradient. It now reads
+  `mat.get_meta("night_energy", 2.0)`, so a multi-strip panel can keep its top-to-bottom ratio
+  (the event banners: 2.6 → 1.4).
 - **Venue lights must keep `omni_attenuation == 1.0`** — `test_world.test_venue_lights_use_physical_falloff`
   enforces physical falloff on every Omni/Spot in all three venues, so a "pool" cannot come from
   sharpening the curve. Use `omni_range` + energy instead: 10 m / energy 8 gives a brighter pool and