servewaf answers rproxy's question about each request and takes its report (closes #170)

`smallwebwaf servewaf` runs today's checks on the visitor's request each
question carries, answers rproxy, and passes nothing to an app. rproxy reports
every request servewaf answered. A report counts an allowed request's bytes and
writes servewaf's second log line. The table holds a copy of what a report
needs, never the request, so a report cannot reach a request being handled.

Judgement call: a question's body is read before any check; over 64 KiB gets 400.
Judgement call: a report's bytes and durations have ceilings, so they cannot overflow.
Judgement call: a `close` disposition for SWWAF_BAN_RESPONSE=close.

Model: opus-5-5

internal/proxy/proxy_test.go

@@ -284,6 +284,16 @@ func newProxy(
 ) (*proxy.Server, *output, *alerts.Queue) {
 	t.Helper()
 
+	return newServerWith(t, proxy.New, appURL, geojsURL, now, env)
+}
+
+// newServerWith is newProxy for the server build makes.
+func newServerWith(
+	t *testing.T, build func(proxy.Params) *proxy.Server,
+	appURL, geojsURL string, now func() time.Time, env map[string]string,
+) (*proxy.Server, *output, *alerts.Queue) {
+	t.Helper()
+
 	settings := map[string]string{
 		"SWWAF_UPSTREAM_URL": appURL, rulesDir: t.TempDir(), instanceName: "app",
 		wafMode: off,
@@ -334,7 +344,7 @@ func newProxy(
 		}
 	}
 
-	server := proxy.New(proxy.Params{
+	server := build(proxy.Params{
 		Config:       cfg,
 		RequestLog:   out,
 		ProcessLog:   processLog,