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/rproxy/rproxy.go

@@ -1,9 +1,10 @@
 // Package rproxy is the reverse proxy in front of one app that asks waf
 // about each request. It passes a request waf allows to the app and the
 // app's answer back, within the size and time limits. Any other answer from
-// waf goes to the visitor as waf gave it. SWW_RPROXY_DEFAULT_DISPOSITION
-// decides only when waf cannot be connected to, does not answer at all, or
-// does not answer within SWW_RPROXY_TIMEOUT_MS. rproxy itself refuses a request with a
+// waf goes to the visitor as waf gave it.
+// SWW_RPROXY_WAF_BACKEND_NO_ANSWER_DISPOSITION decides only when waf cannot
+// be connected to, does not answer at all, or does not answer within
+// SWW_RPROXY_WAF_BACKEND_TIMEOUT_MS. rproxy itself refuses a request with a
 // method it does not pass on, or one it cannot put to waf as the visitor
 // sent it. It keeps nothing between requests and writes nothing to disk. "rproxy" in
 // SPEC.md says what it does.
@@ -108,8 +109,8 @@ func New(params Params) *Server {
 }
 
 // WaitForReports returns once the reports being sent have gone or failed,
-// which SWW_RPROXY_TIMEOUT_MS bounds. Any report after this call is dropped: that of
-// a WebSocket that closes while rproxy stops, for one.
+// which SWW_RPROXY_WAF_BACKEND_TIMEOUT_MS bounds. Any report after this call
+// is dropped: that of a WebSocket that closes while rproxy stops, for one.
 func (s *Server) WaitForReports() {
 	s.h.reportsMu.Lock()
 	s.h.reportsStopped = true
@@ -218,7 +219,8 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 // passToApp passes the request on to the app, unless a limit or its path keeps
 // it from the app. waf answers a path under ownEndpointPrefix itself, so
-// such a request gets here only when SWW_RPROXY_DEFAULT_DISPOSITION allowed it.
+// such a request gets here only when
+// SWW_RPROXY_WAF_BACKEND_NO_ANSWER_DISPOSITION allowed it.
 // ctx is the request's own context.
 func (rq *request) passToApp(ctx context.Context) {
 	maxBytes := rq.h.config.MaxRequestSize