Onboarding · Flows and highlights: wizard, hotspot, highlight, setup checklist

OnboardingWizard runs a first run on navigation::Wizard without its
numbered steps: "Step 2 of 4" over a bar in as many parts, the step's
title, line and content, Back and Next once ready, Finish last, and
Skip for now. Hotspot pulses on a dot that opens a tip on a press or
Enter, with Got it. FeatureHighlight names something new under a New
badge, with Try it and Not now, and rises in. SetupChecklist counts
first things to do in words and a bar, offers Start on each left, eases
a check in as one gets done, and offers Hide once all are.

navigation::Wizard now keys its buttons, steps and motion by its own id
and takes on_step and on_finish at render, failing loud without them.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

TASKS.md

@@ -128,7 +128,8 @@ Per-component lines live in `tasks/`. Tags there:
 - [x] T36a Account · Sign in — `tasks/ch31-43.md`
 - [x] T36b Account · Profile and access — `tasks/ch31-43.md`
 - [x] T36c Account · Billing and team — `tasks/ch31-43.md`
-- [ ] T37 Onboarding & Help
+- [ ] T37a Onboarding · Flows and highlights
+- [ ] T37b Onboarding · Help
 - [ ] T38 Interaction
 - [ ] T39 Theme
 - [ ] T40 i18n & a11y