Reach the handbook from every page, and check the screenshots still tell the truth

[NiKrause]

Two things that belong together, both to be done before the next release.

The handbook is a dead end after the first screen

It is linked once, from the start page (src/routes/+page.svelte:121, data-testid="start-handbook"). Nothing in +layout.svelte links it, so from the programme, the bookings or the connect screen there is no way to reach it — which is exactly where somebody gets stuck and wants it.

The navigation already carries outward links of this kind (nav-source, nav-legal). A nav-handbook next to them is the obvious home.

The screenshots are drifting, and nothing says so

e2e/screenshots.spec.js generates them by driving the real app — good, and deliberately excluded from the normal suite, because it writes files and asserts almost nothing. The cost of that exclusion is that nothing ever checks them. They go stale silently.

Measured today:

Screenshots in the handbook	23
Last regenerated	2026-08-16 (c2d5da4)
Commits on main since	29

Several of those 29 changed what a screen looks like — the Today tab (#93), the relay checkbox (#103), the import panel folding shut (#107), and the bookings tabs now in flight. At least some of the 23 are showing an app that no longer exists.

Scope

• nav-handbook in +layout.svelte, so the handbook is reachable from every screen
• Re-run pnpm run screenshots and look at all 23, rather than assuming regeneration is enough — a generator can photograph a blank panel
• Decide whether staleness should be detectable at all. Options: run the generator in CI and fail on a diff (noisy — timestamps and antialiasing move), or simply note the commit that last regenerated them and flag when it falls too far behind
• Check the handbook text against the app while there, not only the pictures

Timing

Gated on the next release, whose date is not fixed yet — being worked out during the current iteration. Doing it earlier means doing it twice.