feat(web): 纳入 @lunar/core 排盘核心并批准 esbuild 构建脚本

web-commercial 依赖 file:../web/packages/core，此前 web/ 被 gitignore，
干净 worktree 无法构建商业前端；同时将 esbuild 加入 allowBuilds。

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web/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "lunar-calendar",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "description": "万年历 - Chinese Almanac Calendar App",
+  "scripts": {
+    "dev": "pnpm --filter @lunar/web dev",
+    "build": "pnpm --filter @lunar/core build && pnpm --filter @lunar/web build",
+    "preview": "pnpm --filter @lunar/web preview",
+    "test": "pnpm -r test",
+    "lint": "pnpm -r lint",
+    "clean": "pnpm -r clean"
+  },
+  "engines": {
+    "node": ">=18",
+    "pnpm": ">=9"
+  },
+  "devDependencies": {
+    "@eslint/js": "^10.0.1",
+    "eslint": "^10.8.0",
+    "typescript-eslint": "^8.65.0"
+  }
+}