chore(samples): mark sample apps private so publish only ships sample-lib-*

Sample apps (web-*, backend, cloud, extension) are scaffold sources, not npm
packages — create-cpp.js bundles them as templates. Marking them `private: true`
(playgrounds already are) makes `pnpm publish` skip them automatically. Only the
demo C++ libraries (`@cpp.js/sample-lib-*`), which scaffolded projects install
as a dependency, stay publishable.

Author: bugra9

cppjs-samples/cppjs-sample-backend-nodejs-wasm/package.json

@@ -1,5 +1,6 @@
 {
     "name": "@cpp.js/sample-backend-nodejs-wasm",
+    "private": true,
     "version": "2.0.0-beta.15",
     "description": "Cpp.js - Node.js webassembly sample",
     "homepage": "https://github.com/bugra9/cpp.js/tree/main/packages/cppjs-sample-backend-nodejs-wasm#readme",

cppjs-samples/cppjs-sample-cloud-cloudflare-worker/package.json

@@ -1,5 +1,6 @@
 {
     "name": "@cpp.js/sample-cloud-cloudflare-worker",
+    "private": true,
     "version": "2.0.0-beta.15",
     "description": "Cpp.js - Cloudflare webassembly sample",
     "homepage": "https://github.com/bugra9/cpp.js/tree/main/packages/cppjs-sample-cloud-cloudflare-worker#readme",

cppjs-samples/cppjs-sample-extension-pthread/package.json

@@ -1,4 +1,5 @@
 {
     "name": "@cpp.js/sample-extension-pthread",
+    "private": true,
     "main": "index.mjs"
 }

cppjs-samples/cppjs-sample-web-react-rspack/package.json

@@ -1,5 +1,6 @@
 {
     "name": "@cpp.js/sample-web-react-rspack",
+    "private": true,
     "version": "2.0.0-beta.15",
     "description": "Cpp.js React Rspack sample",
     "homepage": "https://github.com/bugra9/cpp.js/tree/main/packages/cppjs-sample-web-react-rspack#readme",

cppjs-samples/cppjs-sample-web-react-vite/package.json

@@ -1,5 +1,6 @@
 {
     "name": "@cpp.js/sample-web-react-vite",
+    "private": true,
     "version": "2.0.0-beta.15",
     "description": "Cpp.js React Vite sample",
     "homepage": "https://github.com/bugra9/cpp.js/tree/main/packages/cppjs-sample-web-react-vite#readme",

cppjs-samples/cppjs-sample-web-svelte-vite/package.json

@@ -1,5 +1,6 @@
 {
     "name": "@cpp.js/sample-web-svelte-vite",
+    "private": true,
     "version": "2.0.0-beta.15",
     "description": "Cpp.js Svelte Vite sample",
     "homepage": "https://github.com/bugra9/cpp.js/tree/main/packages/cppjs-sample-web-svelte-vite#readme",

cppjs-samples/cppjs-sample-web-vanilla/package.json

@@ -1,5 +1,6 @@
 {
     "name": "@cpp.js/sample-web-vanilla",
+    "private": true,
     "version": "2.0.0-beta.15",
     "description": "Cpp.js Web Vanilla sample",
     "homepage": "https://github.com/bugra9/cpp.js/tree/main/packages/cppjs-sample-web-vanilla#readme",

cppjs-samples/cppjs-sample-web-vue-vite/package.json

@@ -1,5 +1,6 @@
 {
     "name": "@cpp.js/sample-web-vue-vite",
+    "private": true,
     "version": "2.0.0-beta.15",
     "description": "Cpp.js Vue Vite sample",
     "homepage": "https://github.com/bugra9/cpp.js/tree/main/packages/cppjs-sample-web-vue-vite#readme",