fix: add playground vercel.json and fix build scripts

- Add vercel.json for playground app to configure Vercel deployment
- Add build:playground script to build playground and its dependencies
- Fix build:web to use ... suffix for building dependencies first

apps/playground/vercel.json

@@ -0,0 +1,5 @@
+{
+  "$schema": "https://openapi.vercel.sh/vercel.json",
+  "buildCommand": "cd ../.. && pnpm -w run build:playground",
+  "installCommand": "pnpm install"
+}

package.json

@@ -31,7 +31,8 @@
   "scripts": {
     "dev": "turbo dev",
     "build": "turbo build",
-    "build:web": "turbo run build --filter=@tpmjs/web",
+    "build:web": "turbo run build --filter=@tpmjs/web...",
+    "build:playground": "turbo run build --filter=@tpmjs/playground...",
     "test": "turbo test",
     "test:ui": "turbo test:ui",
     "lint": "turbo lint",