fix(ci): add @rollup/rollup-linux-x64-gnu as explicit optional dependency

npm lockfile v3 only records platform-specific optional deps for the OS
where the lockfile was generated (macOS). Without a matching manifest
entry in package.json, npm silently skips the rollup linux binary on CI.

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

Author: mikewolfd

package-lock.json

@@ -46,6 +46,9 @@
     "version": "changeset version",
     "release": "npm run build && changeset publish"
   },
+  "optionalDependencies": {
+    "@rollup/rollup-linux-x64-gnu": "4.58.0"
+  },
   "devDependencies": {
     "@changesets/cli": "^2.30.0",
     "@playwright/test": "^1.42.0",