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/anomaly/anomaly.go

@@ -37,13 +37,13 @@ const (
 	ScopeASN = "asn"
 	// ScopeTotal is the whole service.
 	ScopeTotal = "total"
-	// ScopeWatch is a named netblock of SWW_WATCH_NETS.
-	ScopeWatch = "watch"
+	// ScopeWatchedNet is a named netblock of SWW_WATCH_NETS.
+	ScopeWatchedNet = "watched_net"
 )
 
 // Scopes returns every scope.
 func Scopes() []string {
-	return []string{ScopeClient, ScopeNet, ScopeASN, ScopeTotal, ScopeWatch}
+	return []string{ScopeClient, ScopeNet, ScopeASN, ScopeTotal, ScopeWatchedNet}
 }
 
 // The windows a counter counts in, as the alerts name them.
@@ -257,7 +257,7 @@ func (c *Counters) scopesOf(r Request) []scope {
 	for _, named := range p.NamedNetblocks {
 		if named.Netblock.Contains(client) {
 			all = append(all, scope{
-				key{scope: ScopeWatch, netblock: named.Netblock, name: named.Name}, p.Watch,
+				key{scope: ScopeWatchedNet, netblock: named.Netblock, name: named.Name}, p.Watch,
 			})
 		}
 	}
@@ -391,7 +391,7 @@ func alertFor(r Request, k key, o overThreshold) alerts.Alert {
 		detail["asn"] = k.asn
 	case ScopeTotal:
 		counted = "the whole service"
-	default: // watch
+	default: // watched_net
 		counted = "the named netblock " + k.name + ", " + k.netblock.String()
 		detail["name"] = k.name
 	}