test: добавить площадку интеграционного тестирования

- добавлены consumer fixtures для React и Next.js
- добавлены typecheck, production build и браузерные smoke-тесты
- добавлена интеграционная проверка в CI

integration/scripts/run-workspaces.mjs

@@ -0,0 +1,31 @@
+import { spawn } from 'node:child_process'
+import process from 'node:process'
+
+import { apps } from './apps.mjs'
+
+const script = process.argv[2]
+const requestedApps = new Set(process.argv.slice(3))
+
+if (!script) {
+  throw new Error('Usage: node scripts/run-workspaces.mjs <script> [app ...]')
+}
+
+const selectedApps = requestedApps.size === 0
+  ? apps
+  : apps.filter(({ id }) => requestedApps.has(id))
+
+for (const { id } of selectedApps) {
+  console.log(`\n[${id}] npm run ${script}`)
+
+  const exitCode = await new Promise((resolve, reject) => {
+    const child = spawn('npm', ['run', script, '--workspace', `@svg-sprites-fixtures/${id}`, '--if-present'], {
+      stdio: 'inherit',
+      shell: process.platform === 'win32',
+    })
+
+    child.once('error', reject)
+    child.once('exit', (code) => resolve(code ?? 1))
+  })
+
+  if (exitCode !== 0) process.exit(exitCode)
+}