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/waf/waf.go

@@ -1,11 +1,11 @@
 // Package waf runs the OWASP Core Rule Set 4.25.0, through Coraza, on the
 // method, the URL with its query and the headers of a request, and on its
-// body while SWWAF_WAF_BODY_LIMIT is set, with the eight changes smallwebwaf
-// makes to it and the exclusions in SWWAF_CORE_RULE_SET_EXCLUSIONS_FILE, as
+// body while SWW_WAF_BODY_LIMIT is set, with the eight changes sww
+// makes to it and the exclusions in SWW_CORE_RULE_SET_EXCLUSIONS_FILE, as
 // "Attack detection" under "Settings" in SPEC.md describes them. It reads no
 // response.
 //
-// smallwebwaf writes only to its state directory, so Coraza is built with
+// sww writes only to its state directory, so Coraza is built with
 // its no_fs_access tag, as the Dockerfile and script/build build it: of a
 // file in a multipart body, Coraza then counts the bytes instead of
 // writing them to the system's temporary directory.
@@ -30,18 +30,18 @@ import (
 	"github.com/corazawaf/coraza/v3/types"
 )
 
-// directives are the Core Rule Set as smallwebwaf runs it, with the
+// directives are the Core Rule Set as sww runs it, with the
 // paranoia level for %d, bodyDirectives for the first %s while
-// SWWAF_WAF_BODY_LIMIT is set, the exclusions file for the second, and
+// SWW_WAF_BODY_LIMIT is set, the exclusions file for the second, and
 // giteaExclusions for the third.
-// Each rule smallwebwaf adds has an id from 900000 to 900999, the ids the
+// Each rule sww adds has an id from 900000 to 900999, the ids the
 // Core Rule Set keeps for the rules that set it up, which
-// SWWAF_WAF_DISABLED_RULES and the exclusions file refuse, so that no
+// SWW_WAF_DISABLED_RULES and the exclusions file refuse, so that no
 // setting switches one off. Coraza joins a line ending in \ to the next,
 // without the spaces at the start of the next.
 const directives = `
-# The engine only detects. smallwebwaf compares the request's anomaly
-# score with SWWAF_WAF_ANOMALY_THRESHOLD itself, in block and detect mode
+# The engine only detects. sww compares the request's anomaly
+# score with SWW_WAF_ANOMALY_THRESHOLD itself, in block and detect mode
 # alike. It reads no body, unless bodyDirectives switch that on.
 SecRuleEngine DetectionOnly
 SecRequestBodyAccess Off
@@ -183,21 +183,21 @@ var cookiesNotRead = []string{"gitea_flash", "redirect_to"}
 
 // Params are what New needs.
 type Params struct {
-	// ParanoiaLevel is SWWAF_WAF_PARANOIA_LEVEL, from 1 to 4.
+	// ParanoiaLevel is SWW_WAF_PARANOIA_LEVEL, from 1 to 4.
 	ParanoiaLevel int
 	// DisabledRules are the ids of the rules switched off
-	// (SWWAF_WAF_DISABLED_RULES).
+	// (SWW_WAF_DISABLED_RULES).
 	DisabledRules []int
 	// BodyLimit is the most of a request body the Core Rule Set reads
-	// (SWWAF_WAF_BODY_LIMIT), 0 while it is off and it reads none.
+	// (SWW_WAF_BODY_LIMIT), 0 while it is off and it reads none.
 	BodyLimit int64
 	// ExclusionsFile is the path of a file of exclusions loaded before the
-	// Core Rule Set's rules (SWWAF_CORE_RULE_SET_EXCLUSIONS_FILE), "" while
+	// Core Rule Set's rules (SWW_CORE_RULE_SET_EXCLUSIONS_FILE), "" while
 	// there is none.
 	ExclusionsFile string
 }
 
-// The ids of smallwebwaf's own rules, which an exclusions file may not
+// The ids of sww's own rules, which an exclusions file may not
 // name.
 const (
 	firstOwnRuleID = 900000
@@ -209,16 +209,16 @@ const (
 // end of a range may have one.
 var numberOrRange = regexp.MustCompile(`(\d+)(?:-\+?(\d+))?`)
 
-// errSmallwebwafRuleID is the error of an exclusions file that names an
-// id of smallwebwaf's own rules.
-var errSmallwebwafRuleID = errors.New("an id of smallwebwaf's own rules")
+// errSwwRuleID is the error of an exclusions file that names an
+// id of sww's own rules.
+var errSwwRuleID = errors.New("an id of sww's own rules")
 
 // errChangesNoRule is the error of an exclusions file that holds a
 // directive that removes or changes rules as it loads, such as
 // SecRuleRemoveById. The Core Rule Set's rules load after the file, so
 // the directive finds none of them.
 var errChangesNoRule = errors.New("the Core Rule Set's rules load after the file; " +
-	"switch a rule off with SWWAF_WAF_DISABLED_RULES, or on some requests " +
+	"switch a rule off with SWW_WAF_DISABLED_RULES, or on some requests " +
 	"with a ctl exclusion")
 
 // directivesIn returns the directives in text as Coraza reads them: it
@@ -249,7 +249,7 @@ func directivesIn(text string) []string {
 }
 
 // checkExclusions returns an error if exclusions, the text of an
-// exclusions file, names an id of smallwebwaf's own rules, alone or in a
+// exclusions file, names an id of sww's own rules, alone or in a
 // range, or holds a directive whose name starts with SecRuleRemove or
 // SecRuleUpdate.
 func checkExclusions(exclusions string) error {
@@ -264,7 +264,7 @@ func checkExclusions(exclusions string) error {
 
 			if first <= lastOwnRuleID && last >= firstOwnRuleID {
 				return fmt.Errorf("the exclusions file names %s: %w", match[0],
-					errSmallwebwafRuleID)
+					errSwwRuleID)
 			}
 		}
 
@@ -404,7 +404,7 @@ func (c *CoreRuleSet) Inspect(
 }
 
 // readBody reads body, the body of the request in tx, which has run on
-// the request's headers, while SWWAF_WAF_BODY_LIMIT is set and the body is
+// the request's headers, while SWW_WAF_BODY_LIMIT is set and the body is
 // of a kind the Core Rule Set reads: form data and multipart, of which it
 // reads the first c.bodyLimit bytes, and JSON and XML, which it reads only
 // when they are no longer than that, since they cannot be read in part.