fix: Ignore "Premature close" stream errors in Sentry (#12424)

Client disconnects mid-response surface as "Premature close" errors from
Node's stream end-of-stream helper. These are expected and add noise to
Sentry, similar to the EPIPE/ECONNRESET errors already filtered.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

server/logging/sentry.ts

@@ -25,6 +25,9 @@ if (env.SENTRY_DSN) {
       "AuthRedirectError",
       "UserSuspendedError",
       "TooManyRequestsError",
+
+      // Client disconnects
+      "Premature close",
     ],
     beforeSend(event) {
       try {