feat(core): parse P1 workbook and build T-type pier shape

- parse Excel input by header strings (pier, IP, bearing tables)
- DMS azimuth parser (E03), input validation (E01, E02)
- pure geometry: axis, bearings, stepped coping, column, footing, piles, blinding
- warnings W01, W02, W05, W07, I01
- regression tests against spec.md section 12 (P1)

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>

package.json

@@ -0,0 +1,27 @@
+{
+  "name": "pierzainer-3d-drawing",
+  "version": "0.1.0",
+  "description": "교각 3D 형상 생성 웹앱 (1단계: 형상 생성)",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc --noEmit && vite build",
+    "typecheck": "tsc --noEmit",
+    "test": "vitest run"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "type": "module",
+  "dependencies": {
+    "three": "^0.186.1",
+    "xlsx": "^0.18.5"
+  },
+  "devDependencies": {
+    "@types/node": "^26.6.5",
+    "@types/three": "^0.186.0",
+    "typescript": "^7.0.2",
+    "vite": "^8.3.5",
+    "vitest": "^5.0.5"
+  },
+  "private": true
+}