Decide the canonical runtime image root (ADR-0014)

assets/images/ is now the runtime root for composed interface/scene art:
ui/ for screen and panel art, scenes/ for full-frame scene art. Tiled PBR
textures remain under assets/textures/; docs/screens/designs and concepts stay
reference-only; QA captures stay under docs/screenshots. Mockups that become
runtime art are copied/processed with a new name (no overwrites) and always
have a code fallback.

Records the convention in MEMORY, adds ADR-0014 to the architecture index, and
closes the first storage-restructure TODO item.

MEMORY.md

@@ -38,6 +38,12 @@ Session memory for durable decisions, state, and gotchas. Keep concise, remove o
   avatars. Head-turn offsets use `+basis.z` for the same reason. Covered by
   `test_yaw_faces_the_movement_direction`.
 
+- **Image root (ADR-0014, 2026-11-01):** `assets/images/` is the runtime root for composed
+  interface/scene art (`ui/`, `scenes/`); tiled PBR textures stay under `assets/textures/`;
+  `docs/screens/designs/` and `docs/screens/concepts/` stay reference-only; QA captures stay in
+  `docs/screenshots/`. When a mockup becomes runtime art, copy/process it into `assets/images/`
+  with a new name (no overwrites) and keep a fallback in code.
+
 ## Handoff (read this first)
 
 - **Visual-alignment pass planned (2026-11-01):** `TODO.md` gains a "Visual