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 SWW_COMMAND setting, the OS user, and the state
and rules directories.

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"
@@ -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",
 		},
 	}
 }