review classifier: the most classifications a run carries is a setting

The limit was a constant of ten in swarm-wire, so a repo with eleven rules
could not be reviewed and nothing short of a rebuild changed it. It is now
`max_classifications` in the classifier settings, beside
`max_concurrent_reviews`: 1 to 1000, ten until set, and a document stored
before the field decodes with the default. The classifier settings form in
the swarm UI gets a "rules per review" field, and the try-out's add button
stops at the saved limit instead of a hard-coded ten.

The controller checks a try-out, and a requested review's rules file, against
the setting where the run starts. The rules file itself may hold up to the
1000 the setting allows, so raising the limit needs no change to a repo.
A review whose rules exceed the limit posts a no-verdict comment saying so.

A run's reply deadline was a constant that covered ten classifications, a
minute plus three each. It is now computed from the run's own size, so a
bigger run waits as long as it needs and a default-sized one still waits 31
minutes. The classifier's answer window in the queue permissions covers the
biggest run the setting allows.

docs/2-handbook/swarm/ui.md

@@ -261,8 +261,9 @@ repo's default branch, so you can run the repo's own rules or start from them
 and edit. It reads the file each time, so a rule merged a minute ago shows up.
 The page names the file and the commit it read, and asks before it replaces
 classifications you have written. If the repo has no rules file, the file
-doesn't parse, or it holds more than ten rules, the page shows the reason and
-leaves your classifications as they were.
+doesn't parse, or it holds more than a thousand rules, the page shows the reason and
+leaves your classifications as they were. **add a classification** stops at the
+**rules per review** limit of the classifier settings below, ten until set.
 
 A run takes a minute or more, and up to half an hour for ten classifications.
 The page says it's running and shows how long it has been, then lists each classification with its verdict, the model's certainty, the
@@ -302,10 +303,14 @@ cache write prices. The provider's fields sit under their own **provider**
 heading, the URL and the model each on a row of their own and the prices in a
 grid on the same columns as the fields above. The effort is one of low, medium, high, xhigh and max, or
 the runtime's own default. Concurrent reviews is a whole number from 1 to 8;
-try-outs don't count toward it.
+try-outs don't count toward it. Rules per review is the most classifications
+one run carries, a whole number from 1 to 1000, ten until you set it. The
+classifications of a run go one after another, each for up to three minutes, so
+a high limit means a long run. A repo whose rules file holds more than the
+limit gets a no-verdict review, and a try-out with more gets a 400.
 
 **save** is on once something changed and the fields are valid. A save changes
-the runtime, model, effort and limit, and the provider too while the runtime is
+the runtime, model, effort and limits, and the provider too while the runtime is
 ACP, so switching back to API key keeps the stored provider for next time. If
 the controller refuses it, the page shows the reason and leaves the form as you
 typed it. A change takes effect from the next run, with no restart. The page