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.ts

@@ -0,0 +1,19 @@
+// apps/web-next/instrumentation.ts
+// Next.js convention: this module runs once on server boot.
+// Delegates to the centralized init helper in core-shared.
+
+export async function register() {
+  if (
+    process.env["NEXT_RUNTIME"] === "nodejs" ||
+    process.env["NEXT_RUNTIME"] === "edge"
+  ) {
+    const { initSentryServer } = await import(
+      "@repo/core-shared/instrumentation/sentry/init-server"
+    );
+    initSentryServer({
+      dsn: process.env["WEB_NEXT_SENTRY_DSN"],
+      app: "web-next",
+      release: process.env["VERCEL_GIT_COMMIT_SHA"],
+    });
+  }
+}