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

Rename too_large, rate_limited, rule_blocked and denied, and split banned
into temporarily_banned and permanently_banned by whether the ban runs out.
A request that makes a ban permanent gets permanently_banned. A ban the
request itself makes gets the value for that ban, and in observe mode
would_action names the ban enforce mode would have made.

The offence kind rule_blocked follows, as a metric label and a key in
clients.json.

Model: opus-5-5

README.md

@@ -173,7 +173,7 @@ does.
   the request have `"action":"forward"`.
 - To see a refusal without banning yourself, run `discriminator` with
   `SWW_MODE=observe` and ask for `/.env`. The request reaches the app.
-  `discriminator`'s log lines have `"would_action":"banned"` and
+  `discriminator`'s log lines have `"would_action":"temporarily_banned"` and
   `"rule_ids":["env-file"]`. A ban you get in `enforce` mode is lifted as
   "Clients and bans" below describes.
 - With `SWW_METRICS_TOKEN` set, this answers with the metrics, from a host on