Name request log actions so they say what they mean (closes #229)

The request log's `action` values now say what they mean, as sneak named them: `request_header_too_large`, `client_is_rate_limited`, `blocked_by_block_rule` and `client_denied`, with no aliases. `banned` splits into `temporarily_banned` and `permanently_banned`, by whether the ban runs out. When a permanent ban also covers a client, that ban is the one reported.

Trips a reader: a request over a rate limit stays `client_is_rate_limited` even when the ban it makes is permanent.
Disclosure: the offence key `rule_blocked` is renamed in `clients.json` too, so an existing file holding it stops the start and must be removed. Its `version` stays 1.

Model: opus-5-5

internal/discriminator/anomaly_test.go

@@ -187,7 +187,7 @@ func TestEveryRequestIsCountedWhateverIsDoneWithIt(t *testing.T) {
 		{allowed, "/", http.StatusOK, requestlog.ActionForward},
 		{exempt, "/", http.StatusOK, requestlog.ActionForward},
 		{client, "/static/app.js", http.StatusOK, requestlog.ActionForward},
-		{denied, "/", http.StatusForbidden, requestlog.ActionDenied},
+		{denied, "/", http.StatusForbidden, requestlog.ActionClientDenied},
 	} {
 		for range 3 {
 			s.request(sent.from, sent.path, sent.status, sent.action)