feat(mesh): add tile mesh generation package

Add @tts/mesh, a package for generating extruded tile meshes from 2D
shapes. It provides shape generators (rect, hex, circle, rounded rect,
frame), earcut-based tessellation of top/bottom faces with UVs, and
outward-normal wall generation, combined into raw BufferGeometry-ready
typed arrays.

pnpm-lock.yaml

@@ -123,6 +123,25 @@ importers:
         specifier: ^5.7.2
         version: 5.9.3
 
+  packages/mesh:
+    dependencies:
+      earcut:
+        specifier: ^3.2.3
+        version: 3.2.3
+      three:
+        specifier: ^0.185.1
+        version: 0.185.1
+    devDependencies:
+      '@types/earcut':
+        specifier: ^3.0.0
+        version: 3.0.0
+      '@types/three':
+        specifier: ^0.185.4
+        version: 0.185.4
+      typescript:
+        specifier: ^5.7.2
+        version: 5.9.3
+
   packages/shared:
     dependencies:
       zod:
@@ -606,6 +625,9 @@ packages:
   '@types/draco3d@1.4.10':
     resolution: {integrity: sha512-AX22jp8Y7wwaBgAixaSvkoG4M/+PlAcm3Qs4OW8yT9DM4xUpWKeFhLueTAyZF39pviAdcDdeJoACapiAceqNcw==}
 
+  '@types/earcut@3.0.0':
+    resolution: {integrity: sha512-k/9fOUGO39yd2sCjrbAJvGDEQvRwRnQIZlBz43roGwUZo5SHAmyVvSFyaVVZkicRVCaDXPKlbxrUcBuJoSWunQ==}
+
   '@types/estree@1.0.9':
     resolution: {integrity: sha512-GhdPgy1el4/ImP05X05Uw4cw2/M93BCUmnEvWZNStlCzEKME4Fkk+YpoA5OiHNQmoS7Cafb8Xa3Pya8m1Qrzeg==}
 
@@ -743,6 +765,9 @@ packages:
   draco3d@1.5.7:
     resolution: {integrity: sha512-m6WCKt/erDXcw+70IJXnG7M3awwQPAsZvJGX5zY7beBqpELw6RDGkYVU0W43AFxye4pDZ5i2Lbyc/NNGqwjUVQ==}
 
+  earcut@3.2.3:
+    resolution: {integrity: sha512-vnS4AVwp1KHAF13i1vp1/2D5evWy3k5u/iW/B81QVsUZtV8cv2tU0b2VNFlqvh4kYwrFMDdjPCfAmfyJW9y14Q==}
+
   enhanced-resolve@5.24.5:
     resolution: {integrity: sha512-L1l8TNvomm6UVW5B253AGxQagSQr+vGwhMlrrfRS2qmhx46AMpMVJKQYLvWYbysTMY8VoicOvzHzoHMbyzB+4A==}
     engines: {node: '>=10.13.0'}
@@ -1661,6 +1686,8 @@ snapshots:
 
   '@types/draco3d@1.4.10': {}
 
+  '@types/earcut@3.0.0': {}
+
   '@types/estree@1.0.9': {}
 
   '@types/node@22.20.1':
@@ -1792,6 +1819,8 @@ snapshots:
 
   draco3d@1.5.7: {}
 
+  earcut@3.2.3: {}
+
   enhanced-resolve@5.24.5:
     dependencies:
       graceful-fs: 4.2.11