LTS-3295: complete .npmrc hardening + bump SDK to latest

- .npmrc: add ignore-scripts=true + engine-strict=true -> all 6 SC-12282
  directives now present (access=restricted is N/A for a public sample).
  ignore-scripts is safe here: these tests run remotely on BrowserStack and
  Edge/Gecko are not supported on our platform, so the local driver-binary
  postinstalls (edgedriver/geckodriver) are not needed.
- package.json: pin browserstack-node-sdk to 1.61.0 (latest; the wdio/NodeBase
  BLU runner relies on package.json and does not override the node-SDK version).
  Add engines.node ">=18" (satisfied by the runner pods and required by
  @wdio/cli 9) so engine-strict has a safe floor that only rejects EOL Node.
- package-lock.json: regenerated for 1.61.0, kept lockfileVersion 2.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: amitsi-bs

.npmrc

@@ -4,16 +4,18 @@
 # access=restricted is intentionally OMITTED — this is a public, customer-facing
 # sample repository, not a published private package.
 #
-# ignore-scripts=true is intentionally DEFERRED. Dependencies fetch driver
-# binaries during postinstall (edgedriver, geckodriver) and esbuild verifies its
-# platform-specific native binary on install; enabling ignore-scripts would break
-# local driver setup. Re-enable if the sample drops these packages.
+# ignore-scripts=true is now safe: these tests run remotely on BrowserStack, and
+# Edge/Gecko are not supported on our platform, so the local driver-binary
+# postinstalls (edgedriver/geckodriver) are not needed. browserstack-node-sdk is
+# pinned to the latest release (1.61.0) so no update-postinstall is needed either.
 #
-# engine-strict=true is intentionally DEFERRED. Customers clone and run this
-# sample on a wide range of Node versions; hard EBADENGINE enforcement on
-# transitive deps would break `npm install` for them. Kept as a warning.
+# engine-strict=true enforces the package.json `engines.node` floor (>=18), which
+# matches our runner pod and what @wdio/cli 9 already requires. Customers on EOL
+# Node (<18) get a clear upgrade message instead of obscure failures.
 
 strict-ssl=true
 save-exact=true
 audit-level=high
 legacy-peer-deps=false
+ignore-scripts=true
+engine-strict=true