feat(tile): render tiles with the mesh generator

Replace the per-shape tile geometries with @tts/mesh extrusion, honoring
the tile type and stretch aspect ratio. Add extrudeShapeParts so the
caps carry the texture while the walls are solid white, matching TTS
tinting. Fix bottom-face UVs to mirror horizontally and make wall UVs
inherit the front mapping independent of z.

packages/mesh/src/shapes.test.ts

@@ -6,6 +6,7 @@ import {
   polygonShape,
   rectShape,
   roundedRectShape,
+  scaleShape,
   shapeFromThree,
   signedArea,
 } from './shapes.js';
@@ -67,6 +68,19 @@ describe('shape generators', () => {
     expect(signedArea(s.holes![0]!)).toBeLessThan(0);
   });
 
+  it('scaleShape scales outline and holes', () => {
+    const s = scaleShape(rectShape(2, 2), 2, 3);
+    expect(s.outline).toEqual([
+      [-2, -3],
+      [2, -3],
+      [2, 3],
+      [-2, 3],
+    ]);
+    const framed = scaleShape(frameShape(4, 4, 2), 2, 2);
+    expect(framed.holes).toHaveLength(1);
+    expect(framed.holes![0]![0]).toEqual([-2, -2]);
+  });
+
   it('shapeFromThree converts three.js vectors', () => {
     const fake = {
       getPoints: () => [