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/reputation/reputation.go

@@ -371,7 +371,7 @@ func (l *Lists) due(listURL string) time.Time {
 // fetch fetches the list at listURL, and notes the try. A good copy takes
 // the place of the one held. A failure leaves that in use, and is counted,
 // logged and raised as a source_failure alert. A fetch cut off as ctx
-// ends, as smallwebwaf stops, is no failure, but is still noted as a try,
+// ends, as sww stops, is no failure, but is still noted as a try,
 // so that a restart waits for it: the server may have had its request.
 func (l *Lists) fetch(ctx context.Context, listURL string) {
 	lines, err := l.get(ctx, listURL)