Tera, because Simulate was already spoken for

Two names in this repo were quietly colliding with things that already ship.

`lumbridge-simulate` is a Rust crate in the private monorepo — the Governor's
memory-admission simulator, with a public product page — and in its vocabulary
a "Scene" is a set of models, not a three.js scene. Naming a 3D engine the same
thing would have put two different meanings on both words at once.

Meanwhile world1.lumbridgecorp.com has been serving <title>Tera — Lumbridge</title>
since before any of this: the world already had a name.

So the map view is Tera, the interiors product is Spaces, an Office is one
building's interior and a Space is a room inside it. ARCHITECTURE.md opens with
that table now, because the next few thousand lines all depend on it.

The Phaser 2D world comes down rather than being migrated. Its tileset is
precisely what stopped it being open-sourceable, and there are no real users to
strand.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -1,9 +1,10 @@
-# Lumbridge Simulate Engine
+# Tera
 
-**Lumbridge Simulate** — a 3D engine for walkable places. Cities from above,
-buildings from inside, one renderer and one asset library.
+The map view of **Lumbridge Simulate** — cities from above, in three.js.
+Its other half, **Spaces**, is the offices you walk into: one engine and one
+asset library, seen from outside and from inside.
 
-Apache 2.0. Runs at [lumbridgecorp.com/live](https://lumbridgecorp.com/live).
+Apache 2.0. Runs at [tera.lumbridgecorp.com](https://tera.lumbridgecorp.com).
 
 ![San Francisco](docs/sf.jpg)
 
@@ -29,8 +30,8 @@ npm run dev
 ## Using the engine
 
 ```ts
-import { createScene } from "@lumbridge/simulate/engine/scene.ts";
-import SAN_FRANCISCO from "@lumbridge/simulate/cities/sf.ts";
+import { createScene } from "@lumbridge/tera/engine/scene.ts";
+import SAN_FRANCISCO from "@lumbridge/tera/cities/sf.ts";
 
 const scene = createScene(canvas, {
   city: SAN_FRANCISCO,