gpu: collect reset-required/row-remap status and classify Xid codes by severity

nvidia-smi exposes reset_status.reset_required and remapped_rows.* only on
newer drivers for Ampere+ GPUs; queried via a separate exec call since an
unrecognized field name fails the whole --query-gpu command and would have
wiped out unrelated telemetry (temp/ECC/power) on older drivers otherwise.

Also refines Xid severity in both the ingest dmesg collector and the
always-on kmsg watcher: Xid 64 (row-remap InfoROM write failure) now
escalates to Critical instead of the generic warning every other Xid got,
and fixes the SAT-window flush path which previously hardcoded "Warning"
and ignored pattern severity entirely.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

audit/internal/collector/dmesg_events.go

@@ -109,6 +109,12 @@ func matchesAny(s string, patterns []*regexp.Regexp) bool {
 }
 
 func dmesgSeverity(msg string) string {
+	if sev, ok := XidSeverity(msg); ok {
+		if sev == "critical" {
+			return statusCritical
+		}
+		return statusWarning
+	}
 	lower := strings.ToLower(msg)
 	switch {
 	case strings.Contains(lower, "panic") ||