Rename the program to sww and its deciding daemon to discriminator (closes #218)

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/alerts/alerts_test.go

@@ -34,9 +34,9 @@ const (
 	// webhookURL is where the alerts are posted, slackURL the Slack
 	// incoming webhook, and ntfyURL the ntfy topic. ntfyToken is the ntfy
 	// token of the tests that set one.
-	webhookURL = "https://alerts.example/smallwebwaf?team=ops"
+	webhookURL = "https://alerts.example/sww?team=ops"
 	slackURL   = "https://hooks.slack.example/services/T0123/B4567/abcdef"
-	ntfyURL    = "https://ntfy.example/smallwebwaf-alerts"
+	ntfyURL    = "https://ntfy.example/sww-alerts"
 	ntfyToken  = "tk_0123456789abcdefghijklmnopq"
 	// instance is the instance name every alert gives.
 	instance = "fsn1app1/blog"
@@ -132,7 +132,7 @@ func TestWouldSendOnlyForTheChosenEvents(t *testing.T) {
 
 	if q.WouldSend(alerts.EventBan, netblock(1)) ||
 		q.WouldSend(alerts.EventPermanentBan, netblock(1)) {
-		t.Error("a ban alert would be sent, though SWWAF_ALERT_EVENTS leaves it out")
+		t.Error("a ban alert would be sent, though SWW_ALERT_EVENTS leaves it out")
 	}
 
 	if !q.WouldSend(alerts.EventFileError, netip.Prefix{}) {
@@ -184,8 +184,8 @@ func TestWouldSendWithOnlySlackOrOnlyNtfySet(t *testing.T) {
 	onlyNtfy.NtfyURL = parseURL(ntfyURL)
 
 	for setting, params := range map[string]alerts.Params{
-		"SWWAF_ALERT_SLACK_WEBHOOK_URL": onlySlack,
-		"SWWAF_ALERT_NTFY_URL":          onlyNtfy,
+		"SWW_ALERT_SLACK_WEBHOOK_URL": onlySlack,
+		"SWW_ALERT_NTFY_URL":          onlyNtfy,
 	} {
 		if !alerts.New(params).WouldSend(alerts.EventBan, netblock(1)) {
 			t.Errorf("a ban alert would not be sent with only %s set", setting)
@@ -359,7 +359,7 @@ func TestAlertsPastTheHourlyLimitAreRolledIntoOneSummary(t *testing.T) {
 			"as_name":  "",
 			"country":  "",
 			"reason": "3 alerts held back in the hour from 2000-01-01T00:00:00Z, " +
-				"past the 2 an hour SWWAF_ALERT_MAX_PER_HOUR allows",
+				"past the 2 an hour SWW_ALERT_MAX_PER_HOUR allows",
 			"detail": map[string]any{
 				"hour":  started,
 				"count": float64(3),
@@ -525,7 +525,7 @@ func TestFailedRequestIsSentAgainWithBackoff(t *testing.T) {
 		wantCounts(t, q, 0, int64(len(want)), 0, 0)
 
 		if !strings.Contains(log.String(),
-			`"msg":"sending an alert to SWWAF_ALERT_WEBHOOK_URL failed"`) {
+			`"msg":"sending an alert to SWW_ALERT_WEBHOOK_URL failed"`) {
 			t.Errorf("process log %q names no failure", log.String())
 		}
 
@@ -595,7 +595,7 @@ func TestRefusedAlertIsGivenUpAndTheNextSent(t *testing.T) {
 		wantCounts(t, q, 1, 3, 0, 1)
 
 		if !strings.Contains(log.String(),
-			`"msg":"gave up an alert SWWAF_ALERT_WEBHOOK_URL refused"`) {
+			`"msg":"gave up an alert SWW_ALERT_WEBHOOK_URL refused"`) {
 			t.Errorf("process log %q names no alert given up", log.String())
 		}
 	})
@@ -619,7 +619,7 @@ func TestFailedRequestIsLoggedWithoutTheURL(t *testing.T) {
 
 		logged := log.String()
 		if !strings.Contains(logged,
-			`"msg":"sending an alert to SWWAF_ALERT_WEBHOOK_URL failed"`) ||
+			`"msg":"sending an alert to SWW_ALERT_WEBHOOK_URL failed"`) ||
 			strings.Contains(logged, "alerts.example") || strings.Contains(logged, "team=ops") {
 			t.Errorf("process log %q names no failure, or names the URL", logged)
 		}
@@ -782,8 +782,8 @@ func TestSlackAndNtfyAreSentTheSummaryAndTheRepeatsHeldBack(t *testing.T) {
 		}
 
 		const summary = "1 alerts held back in the hour from 2000-01-01T00:00:00Z, " +
-			"past the 1 an hour SWWAF_ALERT_MAX_PER_HOUR allows; 1 repeats held back " +
-			"by SWWAF_ALERT_COOLDOWN that no later alert gives\nsuppressed repeats: 1"
+			"past the 1 an hour SWW_ALERT_MAX_PER_HOUR allows; 1 repeats held back " +
+			"by SWW_ALERT_COOLDOWN that no later alert gives\nsuppressed repeats: 1"
 
 		wantSlackMessage(t, slack[1], "*"+instance+": summary*\n"+summary)
 		wantNtfyMessage(t, ntfy[1], instance+": summary", "default bar_chart", summary)
@@ -901,7 +901,7 @@ func TestDestinationThatDoesNotAnswerHoldsUpNeitherOther(t *testing.T) {
 
 		logged := log.String()
 		if !strings.Contains(logged,
-			`"msg":"sending an alert to SWWAF_ALERT_SLACK_WEBHOOK_URL failed"`) ||
+			`"msg":"sending an alert to SWW_ALERT_SLACK_WEBHOOK_URL failed"`) ||
 			strings.Contains(logged, "hooks.slack.example") ||
 			strings.Contains(logged, "T0123") {
 			t.Errorf("process log %q names no failure, or names the URL", logged)
@@ -1254,7 +1254,7 @@ type eventMessage struct {
 	title, priorityAndTag, text string
 }
 
-// anAlertForEachEvent returns an alert for each event SWWAF_ALERT_EVENTS
+// anAlertForEachEvent returns an alert for each event SWW_ALERT_EVENTS
 // names, the first in observe mode, each with its message.
 func anAlertForEachEvent() []eventMessage {
 	return []eventMessage{
@@ -1320,12 +1320,12 @@ func anAlertForEachEvent() []eventMessage {
 				Event:  alerts.EventFileError,
 				Reason: "a rule file has an error, and the rules stay as they were",
 				Detail: map[string]any{
-					"file": "/etc/smallwebwaf/rules.d/50-app.rules", "error": "line 2: no action",
+					"file": "/etc/sww/rules.d/50-app.rules", "error": "line 2: no action",
 				},
 			},
 			"fsn1app1/blog: file_error", "high warning",
 			"a rule file has an error, and the rules stay as they were\n" +
-				"file: /etc/smallwebwaf/rules.d/50-app.rules\nerror: line 2: no action",
+				"file: /etc/sww/rules.d/50-app.rules\nerror: line 2: no action",
 		},
 	}
 }