feat: multi-format 3D viewer with large-file OBJ streaming, Z-up, projection/outline UI

Three.js viewer supporting glb/gltf/obj/fbx/dae/ifc/ply via both server (SSR)
and drag&drop (CSR) paths.

- Streaming OBJ parser (src/viewer/objStream.ts) for files past the V8 max
  string length (>~1GB text) that OBJLoader can't handle; indexed geometry,
  per-vertex color from MTL Kd, float64 recenter baked in.
- In-viewer float64 recenter (objRecenter.ts) for huge CAD/survey coordinates
  (~1e8) so float32 vertex buffers keep precision (no cracked faces).
- Z-up right-handed world; Y-up formats rotated on load.
- OBJ+MTL+texture drag&drop (LoadingManager URL-modifier maps dropped images).
- OrbitControls ground-plane panning (road/rail alignment workflow).
- UI: Zoom Fit, perspective/orthographic toggle, feature-edge outline.
- DoubleSide for CAD OBJ; PLY mesh + point-cloud support.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package.json

@@ -0,0 +1,28 @@
+{
+  "name": "hmwebviewer",
+  "private": true,
+  "version": "0.1.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc --noEmit && vite build",
+    "preview": "vite preview",
+    "typecheck": "tsc --noEmit",
+    "postinstall": "node tools/copy-decoders.mjs"
+  },
+  "dependencies": {
+    "three": "^0.169.0",
+    "web-ifc": "^0.0.77"
+  },
+  "devDependencies": {
+    "@gltf-transform/cli": "^4.4.0",
+    "@gltf-transform/core": "^4.4.0",
+    "@gltf-transform/extensions": "^4.4.0",
+    "@gltf-transform/functions": "^4.4.0",
+    "@types/three": "^0.169.0",
+    "draco3d": "^1.5.7",
+    "puppeteer-core": "^25.1.0",
+    "typescript": "^5.6.0",
+    "vite": "^5.4.0"
+  }
+}