Expand the photo-driven Gaussian splatting map plan

MEMORY.md

@@ -4,6 +4,15 @@ Session memory for durable decisions, state, and gotchas. Keep concise, remove o
 
 ## Decisions
 
+- **Gaussian splatting / photo-derived maps (unversioned local track):** expanded in
+  `TODO.md` "Gaussian splatting evaluation". Accepted photo channels are team captures,
+  permissioned user/volunteer photos and clearly licensed downloads; every set needs a
+  provenance/consent sidecar. Sparse web photos are reference/training supplements, not a splat
+  source. Five enhancement paths are ranked (reference/QA, texture bake, mesh proxy, distant
+  backdrop, single-facade user-photo supplement). Splats stay offline/development-only until the
+  ADR proves licence, privacy, Godot Compatibility/Web cost and mesh-based collision; no runtime
+  splat dependency in 0.10.0.
+
 - **NPC model variety decision (2026-11-03, ADR-0015):** CC0 is acceptable for shipped
   assets; CC-BY only with attribution in `CREDITS.md`; no service assets with redistribution
   restrictions. The **procedural generator is the primary path**. Four crowd-variety specs were