LTS-3294: add min-release-age=7 to .npmrc (clears semgrep npm-missing-minimum-release-age)

Semgrep p/default flagged `npm-missing-minimum-release-age` on this .npmrc — a
supply-chain rule (npm v11.10+) that wants a cooldown before resolving
newly-published package versions. Adding `min-release-age=7` clears it (verified
locally: semgrep p/default now reports 0 findings).

Validated on prod: a real BLU load run with this directive present installed and
ran cleanly (Test ffd17daa..., 266 requests, all browser metrics green), so the
7-day cooldown does not block the pinned SDK on the runner pod (pod npm treats it
as inert today; it activates as supply-chain protection on npm >=11.10).

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

Author: amitsi-bs

.npmrc

@@ -21,3 +21,4 @@ audit-level=high
 legacy-peer-deps=false
 ignore-scripts=true
 engine-strict=true
+min-release-age=7