Rename the program to sww and its deciding daemon to discriminator

The program is now sww, built from cmd/sww, with two modes: sww rproxy and
sww discriminator. servewaf becomes discriminator everywhere it names that
daemon: the package (internal/discriminator), its types, functions, files, the
discriminator_line log field, and its docs and tests.

smallwebwaf is left only where sneak's directive allows it: the documents'
product name, the git.eeqj.de/sneak/smallwebwaf URLs, and the Go module path
sneak.berlin/go/smallwebwaf. Everywhere else a name containing it takes the sww
form: the package (internal/sww), metric names (sww_*), the X-Sww-* headers,
the /_sww/ admin endpoints, the OS user, and the state and rules directories.
The SWWAF_ environment variables take the SWW_ form.

No logic changes. make check passes.

Model: deepseek-v4-pro

internal/remotelog/remotelog_test.go

@@ -586,7 +586,7 @@ func wantRetries(t *testing.T, logged *output, delays ...string) {
 		var fields map[string]any
 
 		err := json.Unmarshal([]byte(line), &fields)
-		if err != nil || fields["msg"] != "sending to SWWAF_LOG_REMOTE_URL failed" {
+		if err != nil || fields["msg"] != "sending to SWW_LOG_REMOTE_URL failed" {
 			t.Fatalf("logged %q", line)
 		}
 
@@ -612,7 +612,7 @@ func testCertificate(t *testing.T) (tls.Certificate, *x509.CertPool) {
 
 	template := &x509.Certificate{
 		SerialNumber:          big.NewInt(1),
-		Subject:               pkix.Name{CommonName: "smallwebwaf test CA"},
+		Subject:               pkix.Name{CommonName: "sww test CA"},
 		NotBefore:             time.Date(1999, 12, 31, 0, 0, 0, 0, time.UTC),
 		NotAfter:              time.Date(2000, 1, 2, 0, 0, 0, 0, time.UTC),
 		IsCA:                  true,