fix: disable strict-store-pkg-content-check for pkg.pr.new tarball compatibility

pnpm store cache in CI holds stale pkg.pr.new tarballs (@nuxt/kit@4.2.2 vs 4.3.1)
causing ERR_PNPM_UNEXPECTED_PKG_CONTENT_IN_STORE failures.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: productdevbook

.npmrc

@@ -0,0 +1 @@
+strict-store-pkg-content-check=false