Show start refusals and the real model in the TUI, stacks for failed runs, route with ruuter

[yogthos]

Starting a run from the TUI blinked "starting…" and showed nothing when the
server refused it: every successful poll cleared :error, and start! polls
straight after the refusal. A poll now clears only an error a lost
connection raised, and a refused start also prints its full reason in the
conversation, since the status strip clips it.

The footer showed the model a run started on, even after it ended, and
gauged the context fill against the server default's window. The run detail
now carries the run's provider, model and window with any live switch
applied, and the project endpoint the provider alias. The footer shows the
running run's model, otherwise the one a start would use, and both gauges
use the run's window. A provider switch named without a model no longer
keeps the previous switch's model.

Run ab935047 died opening the siblings an escalation asked for: a store
call inside a two-collection mapv parked on the DB lock, which jolt raised
on until 0.8.13 (jolt-lang/jolt#1142). 0.8.13 is now the minimum, so the
lazy-body ratchet and the prompt rule telling cells to avoid it are gone.
A failed run's :run-error note now names the cell that threw rather than
the one before it and carries its stack, and the supervisor stream of a
resumed run reads it with the stage crashes, frames included.

The HTTP server routes through ruuter. Handlers are wrapped so a redefined
var still answers the next request, and the table stays a def because
ruuter caches compiled tables by value. proc_test's sweep used a fixed
process name, so two suites on one machine killed each other's child; the
name is now per process.