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

The first half of the naming audit: names now say what they are. `internal/waf` is `internal/coreruleset`. Log fields, the action `blocked_by_core_rule_set`, the metric and the alert event say Core Rule Set. Timings end `_ms`. Percentages say of what, as `rate_limit_percent` and `bytes_limit_percent`. Setting names follow in #234.

Judgement call: `blocked_by_core_rule_set`, not the audit's `core_rule_set_blocked`, to match `blocked_by_block_rule`.
Trips a reader: an existing state file holding `waf_blocked` or the anomaly scope `watch` stops the start and must be removed. `SWW_ALERT_EVENTS` listing `waf_block` must list `core_rule_set_match`.

Model: opus-5-5

internal/lookup/lookup_test.go

@@ -362,7 +362,7 @@ func TestWithoutWaitTheRequestGoesOnAtOnceAndTheAnswerIsGivenWhenItComes(
 		mu.Unlock()
 
 		wantCountry(t, g, client, germany)
-		wantUnanswered(t, m, 0)
+		wantRequestsWithoutGeoJSAnswer(t, m, 0)
 	})
 }
 
@@ -596,7 +596,7 @@ func TestClientsWithoutAnAnswerAreCounted(t *testing.T) {
 		// GeoJS fails, so the first client goes without an answer, and GeoJS
 		// is left alone for a second, which does not pass in this test.
 		wantCountry(t, g, clients(), "")
-		wantUnanswered(t, m, 1)
+		wantRequestsWithoutGeoJSAnswer(t, m, 1)
 
 		// Meanwhile each new client goes without one at once, while there is
 		// room for it among the 10,000 that may wait.
@@ -604,11 +604,11 @@ func TestClientsWithoutAnAnswerAreCounted(t *testing.T) {
 			wantCountry(t, g, clients(), "")
 		}
 
-		wantUnanswered(t, m, 10000)
+		wantRequestsWithoutGeoJSAnswer(t, m, 10000)
 
 		// One more, for which there is no room, goes without one too.
 		wantCountry(t, g, clients(), "")
-		wantUnanswered(t, m, 10001)
+		wantRequestsWithoutGeoJSAnswer(t, m, 10001)
 	})
 }
 
@@ -841,12 +841,12 @@ func wantAsked(t *testing.T, geojs *standIn, i int, want ...string) {
 	}
 }
 
-// wantUnanswered checks how many requests m counts as having gone without
-// an answer from GeoJS.
-func wantUnanswered(t *testing.T, m *metrics.Metrics, want float64) {
+// wantRequestsWithoutGeoJSAnswer checks how many requests m counts as having
+// gone without an answer from GeoJS.
+func wantRequestsWithoutGeoJSAnswer(t *testing.T, m *metrics.Metrics, want float64) {
 	t.Helper()
 
-	got := testutil.ToFloat64(m.GeoJSUnanswered)
+	got := testutil.ToFloat64(m.RequestsWithoutGeoJSAnswer)
 	if got != want {
 		t.Errorf("%v requests went without an answer, want %v", got, want)
 	}