Rename the settings whose names do not say what they control (closes #234)

Applies the setting renames of the naming audit under the SWW_WAF_ and
SWW_RPROXY_ prefixes, with sneak's names for the IP reputation cache
time and the two time limits, which now take milliseconds. The rproxy
log field default_disposition becomes waf_backend_no_answer, and
config.Config and config.FromEnvironment become config.WAF and
config.WAFFromEnvironment. Go fields, test names and prose follow. No
aliases; nothing reads the old names.

Model: opus-5-5

internal/config/rproxy.go

@@ -25,13 +25,15 @@ type RProxy struct {
 	TrustedProxies []netip.Prefix
 	// WAFBackend is waf's URL (SWW_RPROXY_WAF_BACKEND).
 	WAFBackend *url.URL
-	// Timeout is how long rproxy waits for waf's answer to a question,
-	// and to a report (SWW_RPROXY_TIMEOUT_MS). It cannot be off.
-	Timeout time.Duration
-	// DefaultDisposition is what is done with a request when waf cannot be
-	// connected to, does not answer at all, or does not answer within Timeout:
-	// allow or deny (SWW_RPROXY_DEFAULT_DISPOSITION).
-	DefaultDisposition string
+	// WAFBackendTimeout is how long rproxy waits for waf's answer to a
+	// question, and to a report (SWW_RPROXY_WAF_BACKEND_TIMEOUT_MS). It
+	// cannot be off.
+	WAFBackendTimeout time.Duration
+	// WAFBackendNoAnswerDisposition is what is done with a request when waf
+	// cannot be connected to, does not answer at all, or does not answer
+	// within WAFBackendTimeout: allow or deny
+	// (SWW_RPROXY_WAF_BACKEND_NO_ANSWER_DISPOSITION).
+	WAFBackendNoAnswerDisposition string
 	// MaxRequestSize is the largest request body (SWW_RPROXY_MAX_REQUEST_SIZE), and
 	// MaxResponseSize the largest response body (SWW_RPROXY_MAX_RESPONSE_SIZE).
 	MaxRequestSize  int64
@@ -89,9 +91,12 @@ func RProxyFromEnvironment(v *viper.Viper) (*RProxy, error) {
 			privateRanges,
 		),
 		WAFBackend: env.wafBackend("SWW_RPROXY_WAF_BACKEND"),
-		Timeout:    env.milliseconds("SWW_RPROXY_TIMEOUT_MS", "2000"),
-		DefaultDisposition: env.disposition(
-			"SWW_RPROXY_DEFAULT_DISPOSITION",
+		WAFBackendTimeout: env.milliseconds(
+			"SWW_RPROXY_WAF_BACKEND_TIMEOUT_MS",
+			"2000",
+		),
+		WAFBackendNoAnswerDisposition: env.disposition(
+			"SWW_RPROXY_WAF_BACKEND_NO_ANSWER_DISPOSITION",
 			"allow",
 		),
 		MaxRequestSize:  env.size("SWW_RPROXY_MAX_REQUEST_SIZE", "100M"),