fix: address PR review feedback - add type: module, fix .vercelignore, remove unused .npmrc

- Add "type": "module" to package.json for ESM compatibility (Vercel handler is ESM)
- Fix .vercelignore to not exclude build dependencies (server/, scripts/bundle-api.mjs)
- Remove app-specific .npmrc (not honored when install runs from monorepo root)

These changes address feedback from @copilot-pull-request-reviewer:
1. ESM files require "type": "module" in package.json (matches apps/studio pattern)
2. Build script needs access to server/ and scripts/ during Vercel build
3. .npmrc node-linker=hoisted is unnecessary with Turso remote mode (no native modules)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Claude

examples/app-host/.npmrc

@@ -7,16 +7,8 @@ test/
 *.test.ts
 *.spec.ts
 
-# Ignore development files
+# Ignore development-only files that are not required by the Vercel build
 debug-registry.ts
-src/
-
-# Ignore source files (only need the bundle)
-server/
-scripts/bundle-api.mjs
-
-# Ignore metadata (using in-memory driver)
-metadata/
 
 # Keep only the bundled API handler
 !api/_handler.js

examples/app-host/.vercelignore

@@ -2,6 +2,7 @@
   "name": "@example/app-host",
   "version": "4.0.3",
   "license": "Apache-2.0",
+  "type": "module",
   "private": true,
   "scripts": {
     "dev": "objectstack serve --dev",