fix(security): prevent integer overflow in uint64 to int64 conversions

Add overflow checks before converting uint64 memory values to int64
to prevent potential integer overflow issues identified by gosec (G115).

- Add math.MaxInt64 checks in fileproc/backpressure.go
- Add math.MaxInt64 checks in fileproc/resource_monitor_validation.go
- Add math.MaxInt64 checks in fileproc/resource_monitor_metrics.go
- Add math.MaxInt64 check in benchmark/benchmark.go with nosec annotation

Co-authored-by: ivuorinen <11024+ivuorinen@users.noreply.github.com>

fileproc/resource_monitor_concurrency_test.go

@@ -43,11 +43,11 @@ func TestResourceMonitor_ConcurrentReadsLimit(t *testing.T) {
 
 	// Release one slot and try again
 	rm.ReleaseReadSlot()
-	
+
 	// Create new context for the next attempt
 	ctx2, cancel2 := context.WithTimeout(context.Background(), 100*time.Millisecond)
 	defer cancel2()
-	
+
 	err = rm.AcquireReadSlot(ctx2)
 	if err != nil {
 		t.Errorf("Expected no error after releasing a slot, got %v", err)
@@ -92,4 +92,4 @@ func TestResourceMonitor_TimeoutContexts(t *testing.T) {
 	} else if time.Until(deadline) > 2*time.Second+100*time.Millisecond {
 		t.Error("Overall processing timeout appears to be too long")
 	}
-}
+}