Name log fields, metrics and the Core Rule Set package for what they are (closes #192)

Log field, metric, action and event names now say what they count
and, for timings, the unit. Package internal/waf is internal/coreruleset.

Model: opus-5-5

internal/discriminator/refusallimit.go

@@ -28,7 +28,7 @@ func (refusalLimit) check(_ context.Context, rq *request, now time.Time) *verdic
 		return nil
 	}
 
-	if !rq.attack && !rq.blockedByBlockRule && !rq.wafBlocked {
+	if !rq.attack && !rq.blockedByBlockRule && !rq.blockedByCoreRuleSet {
 		return nil
 	}
 
@@ -42,7 +42,7 @@ func (refusalLimit) check(_ context.Context, rq *request, now time.Time) *verdic
 	status := rq.out.status
 
 	switch rq.line.WouldAction {
-	case requestlog.ActionBlockedByBlockRule, requestlog.ActionWAFBlocked:
+	case requestlog.ActionBlockedByBlockRule, requestlog.ActionBlockedByCoreRuleSet:
 		status = http.StatusForbidden
 	case requestlog.ActionTemporarilyBanned, requestlog.ActionPermanentlyBanned:
 		status = cfg.BanResponse