feat(console): the guided setup steps backwards

[stormer78]

be good on the guided flow to be able to go back a step to add more attributes for example

The route existed and was called Cancel — which reads as abandoning setup, not stepping back one — and the affordance a person actually reaches for, the ticked circle in the stepper, did nothing at all.

The stepper answers clicks

A step you could be on is a way to get there:

Step	Reachable when
1 · Add a fact or two	always
2 · Make a face	a fact exists
3 · Be known somewhere	a face exists

Reaching a step with nothing to work on presents a form whose every control refuses, which is a worse answer than not offering the step. reachableStep decides, in persona-flow.ts beside showsGuide, with four tests.

The buttons say where they go

Step two's is now "Back — add more facts", step three's "Back — change the face". Both said "Cancel", and step three's left the guide entirely rather than going back — pressing it after making a face dropped you on the map, which is not what cancel means at step three of three.

Step two edits the face once there is one

So going back to it does not quietly create a second face. The editor already supports this — the same existing path the map uses — and it seeds its ticks from the face, so a holder who goes back to add a fact returns to find their earlier choices intact with the new fact unticked. Which is exactly what "a face is a whitelist; what you leave unticked stays out, including facts you add later" means, now demonstrated rather than only asserted in the copy.

Step one no longer offers Cancel

There is nothing before it, and the button abandoned the whole flow. AttributeEditor's onCancel is optional now and renders nothing when omitted; the header's "Skip — I'll build it myself" is the single, honestly labelled exit.

Verification

npm run lint, npm run build, npm test — 849 across four workspaces (+4). All six ci.yml assertions against the real build.

The reachability rule is tested; the click handling on the stepper is not — no renderer here, as before.