Fix local npm installs and bump next to 16.4.2 (#64429)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: cad62657-5a77-4f22-b274-41bb68ec5bb6

Author: heiskr

.npmrc

@@ -4,6 +4,10 @@
 audit=false
 fund=false
 
+# Use the public registry even when a global npm config points elsewhere,
+# so npm ci fetches the same packages as CI and the Docker build.
+registry=https://registry.npmjs.org/
+
 # Skip package versions published in the last 7 days, matching the Dependabot cooldown.
 # Needs npm 11.10 or later.
 min-release-age=7

package-lock.json

@@ -222,7 +222,7 @@
     "mdast-util-to-hast": "^13.2.1",
     "mdast-util-to-markdown": "2.1.2",
     "mdast-util-to-string": "^4.0.0",
-    "next": "^16.4.1",
+    "next": "^16.4.2",
     "parse5": "8.0.1",
     "pele": "1.3.0",
     "quick-lru": "7.0.1",