AbuseIPDB scores for clients that committed an offence, within a daily budget (closes #105)

With SWWAF_ABUSEIPDB_KEY set, a client whose history counts an offence
(a broken limit, a ban rule's match or a block rule's refusal, counted
by kind) is checked in the background, at most
SWWAF_ABUSEIPDB_DAILY_BUDGET checks a day, the count kept in
reputation.json. A client, an IPv4 address or an IPv6 /64, is checked by
the address it sent from, and its score serves all its addresses. A
score at or over SWWAF_ABUSEIPDB_MIN_SCORE is a hit for
SWWAF_REPUTATION_ACTION, logged as abuseipdb and alerted with its score.
A failure or the used-up budget gives no score and raises
source_failure. The key goes only in the Key header.

Judgement call: the budget's day is UTC; AbuseIPDB documents no reset time.
Judgement call: each check sent spends budget; a minute's pause after a failure.

Model: opus-5-5

internal/smallwebwaf/smallwebwaf.go

@@ -21,6 +21,7 @@ import (
 	"sneak.berlin/go/smallwebwaf/internal/lookup"
 	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/remotelog"
+	"sneak.berlin/go/smallwebwaf/internal/reputation"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 	"sneak.berlin/go/smallwebwaf/internal/rules"
 	"sneak.berlin/go/smallwebwaf/internal/state"
@@ -169,14 +170,15 @@ func newServer(
 	}
 
 	server := proxy.New(proxy.Params{
-		Config:     cfg,
-		RequestLog: stdout,
-		ProcessLog: processLog,
-		GeoJSURL:   lookup.URL,
-		LookupFile: lookupFile,
-		Now:        now,
-		Rules:      ruleFiles,
-		Alerts:     alertQueue,
+		Config:       cfg,
+		RequestLog:   stdout,
+		ProcessLog:   processLog,
+		GeoJSURL:     lookup.URL,
+		AbuseIPDBURL: reputation.AbuseIPDBURL,
+		LookupFile:   lookupFile,
+		Now:          now,
+		Rules:        ruleFiles,
+		Alerts:       alertQueue,
 	})
 	server.Metrics.AddAlerts(alertQueue)
 
@@ -202,6 +204,7 @@ func loadStateFiles(
 		GeoJS:           server.GeoJS,
 		Lists:           server.Lists,
 		DNSBL:           server.DNSBL,
+		AbuseIPDB:       server.AbuseIPDB,
 		Alerts:          alertQueue,
 		Anomalies:       server.Anomalies,
 		Now:             now,