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/bans/bans.go

@@ -1,4 +1,4 @@
-// Package bans is the ban ledger: the bans smallwebwaf makes on the
+// Package bans is the ban ledger: the bans sww makes on the
 // netblocks of clients that break a rate limit, a byte limit or the error
 // burst, show a clear sign of attack or are listed by the CrowdSec
 // decision list, and
@@ -21,14 +21,14 @@ import (
 
 // The causes of bans.
 const (
-	// CauseLimit is a ban smallwebwaf made for a broken limit.
+	// CauseLimit is a ban sww made for a broken limit.
 	CauseLimit = "limit"
-	// CauseAttack is a ban smallwebwaf made for a clear sign of attack.
+	// CauseAttack is a ban sww made for a clear sign of attack.
 	CauseAttack = "attack"
-	// CauseAdmin is a ban an admin made, or one smallwebwaf made that an
+	// CauseAdmin is a ban an admin made, or one sww made that an
 	// admin keeps. It is never dropped.
 	CauseAdmin = "admin"
-	// CauseCrowdSec is a ban smallwebwaf made for a client the CrowdSec
+	// CauseCrowdSec is a ban sww made for a client the CrowdSec
 	// decision list lists. It ends when CrowdSec's decision does.
 	CauseCrowdSec = "crowdsec"
 )
@@ -70,7 +70,7 @@ type Ban struct {
 	Expires time.Time
 	// Cause is CauseLimit, CauseAttack, CauseAdmin or CauseCrowdSec.
 	Cause string
-	// Reason is a short text: for a ban smallwebwaf made, the limit broken,
+	// Reason is a short text: for a ban sww made, the limit broken,
 	// the rule that matched or the scenario of CrowdSec's decision; for an
 	// admin's, what the admin wrote.
 	Reason string
@@ -123,7 +123,7 @@ type Notes struct {
 	LimitPercentSetting string `json:"limit_percent_setting,omitempty"`
 	// RuleID and Target are, for a ban for a clear sign of attack, the id
 	// of the rule file rule that matched, and its target; TrapPath is, for
-	// one for a request for a path in SWWAF_TRAP_PATHS, that path as the
+	// one for a request for a path in SWW_TRAP_PATHS, that path as the
 	// client sent it.
 	RuleID   string `json:"rule_id,omitempty"`
 	Target   string `json:"target,omitempty"`
@@ -199,7 +199,7 @@ type Ledger struct {
 	// v4Lengths and v6Lengths are the lengths of the IPv4 and IPv6
 	// netblocks that have been banned. Check looks for a ban at each of
 	// them, so that a ban read from bans.json refuses every client in its
-	// netblock even when it was made with another SWWAF_BAN_SCOPE_V4_PREFIX,
+	// netblock even when it was made with another SWW_BAN_SCOPE_V4_PREFIX,
 	// or another length of an IPv6 client's netblock.
 	v4Lengths, v6Lengths []int
 }
@@ -581,7 +581,7 @@ func (l *Ledger) Load(bans []Ban) {
 }
 
 // LoadEdit is Load for an admin's edit of bans.json, taken in while
-// smallwebwaf runs. Each ban in it whose cause is CauseAdmin, and which
+// sww runs. Each ban in it whose cause is CauseAdmin, and which
 // the ledger did not hold, with the same netblock and start, is one the
 // admin made, and is counted among the bans made.
 func (l *Ledger) LoadEdit(bans []Ban) {