Rename internal/proxy to internal/servewaf (closes #173)

The package passes nothing to an app since rproxy took that over, so it
is named after the command it serves. The rproxy tests call their
stand-in for servewaf standIn, since a local servewaf would hide the
package. No change of behaviour.

Model: opus-5-5

internal/servewaf/countries.go

@@ -0,0 +1,21 @@
+package servewaf
+
+import (
+	"slices"
+)
+
+// countryDenied reports whether the country lists refuse the request, by
+// the client's country as it was looked up. A client without a country,
+// or whose country cannot be found, is refused only by
+// SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES.
+func (rq *request) countryDenied() bool {
+	denied := rq.h.config.DeniedCountries
+	allowed := rq.h.config.ExclusivelyAllowedCountries
+	country := rq.line.Country
+
+	if slices.Contains(denied, country) {
+		return true
+	}
+
+	return len(allowed) > 0 && !slices.Contains(allowed, country)
+}