feat(web-next): Sentry instrumentation hooks + withSentryConfig + R38 PII test

Adds apps/web-next/instrumentation.ts (server) and instrumentation-client.ts
(browser) hooks, wraps next.config.mjs with withSentryConfig (R52), and adds
the R38 per-app PII scrubber smoke test.

Spec deviation: extend PII_KEY_SUBSTRINGS with "ipaddress" so keys like
ipAddress trigger key-level redaction (tighter posture than the spec's
substring list; existing scrub.test.ts still passes).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web-next/instrumentation-client.ts

@@ -0,0 +1,10 @@
+// apps/web-next/instrumentation-client.ts
+// Next.js 15+ browser hook: runs in the client bundle on app start.
+
+import { initSentryClient } from "@repo/core-shared/instrumentation/sentry/init-client";
+
+initSentryClient({
+  dsn: process.env["NEXT_PUBLIC_WEB_NEXT_SENTRY_DSN"],
+  app: "web-next",
+  release: process.env["NEXT_PUBLIC_VERCEL_GIT_COMMIT_SHA"],
+});