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/reputation/reputation_test.go

@@ -34,8 +34,8 @@ const (
 	dropURL = "https://lists.example/drop.txt"
 	torURL  = "https://lists.example/tor.txt"
 	asnURL  = "https://lists.example/asn.txt"
-	// refresh is the tests' SWWAF_BLOCKLIST_REFRESH, and cooldown their
-	// SWWAF_ALERT_COOLDOWN, longer than it.
+	// refresh is the tests' SWW_BLOCKLIST_REFRESH, and cooldown their
+	// SWW_ALERT_COOLDOWN, longer than it.
 	refresh  = 24 * time.Hour
 	cooldown = 48 * time.Hour
 	// drop is a blocklist as the Spamhaus DROP list is written, with an
@@ -116,7 +116,7 @@ func TestClientIsListedByEachBlocklistThatListsIt(t *testing.T) {
 		}}
 		lists := start(t, servers, params(torURL, dropURL))
 
-		// In the order SWWAF_BLOCKLIST_URLS names them.
+		// In the order SWW_BLOCKLIST_URLS names them.
 		wantListedBy(t, lists, "203.0.113.9", torURL, dropURL)
 		wantListedBy(t, lists, "203.0.113.8", dropURL)
 	})