feat(frontend): separate Dashboard from All Hackathons, and drop About from the navbar

[hanaCasey]

Why

The logged-in navbar's two primary entries were hard to tell apart. Dashboard and Hackathons are both nouns for a list of hackathons, and neither word says whose — plus the bar's own wordmark reads "Hackathons", so the noun appeared twice in one row: once as the platform, once as a page inside it. History says this has bitten before (the entry once resolved to the dashboard when signed in, making the browse page unreachable from the chrome for anyone with an account). Giving them two destinations stopped them fighting; it did not make them distinguishable.

What changed

components/frontend/src/lib/components/layout/NavBar.svelte only — no restyling elsewhere.

1. The pair is separated three ways instead of one

	Dashboard	All Hackathons
label	Dashboard (unchanged)	Hackathons → All Hackathons
icon	layout-dashboard	compass
hint	"The events you're part of"	"Every event on the platform, searchable"

• The label states the scope, and states it the same way signed in or out — a word that renames itself with your session is the same bug as one that re-points itself.
• The icons carry the distinction before either label is read; both are decorative (aria-hidden), so accessible names are unchanged.
• The hint is a title on the desktop bar and visible text in the mobile panel — a phone has no hover, so a tooltip-only explanation would reach nobody there. Panel rows moved from h-10 to min-h-10 + padding so the second line cannot be clipped; single-line rows keep their 2.5rem.
• Active state is unchanged in kind (accent underline + aria-current="page"), but now spans icon and label.

2. About is out of the navbar — the page is untouched

It stays a CMS-backed, organiser-editable SitePage, and it was already linked from AppFooter's Platform column, which AppShell renders for the (app) group as well as (public) — verified, not assumed. Privacy and Terms are the same kind of page and were never in the bar either. The "every entry present on every page" rule still holds: it forbids an entry that appears and disappears as you move through the app, not one that is consistently absent and linked from the footer.

Net width at the md breakpoint is roughly unchanged: the icons and the longer label cost about what About's entry freed.

3. Specs and docs follow the change

• .claude/skills/hackathon-e2e/tests/smoke/02-login.spec.ts — re-specified, not trimmed. It asserted About was in the bar; it now asserts the two entries by their new names, counts the bar's links (so a third entry has to argue for itself here first), and adds the claim this removal actually rests on: About absent from the header and reachable from the footer on both a public and a signed-in page, clicked rather than read off an href. The footer locator is scoped to the Platform column — the SDSC column beside it links datascience.ch's own About, so a footer-wide match resolves two links.
• .claude/CLAUDE.md — the "Nav IA is one meaning per entry" note said Dashboard, Hackathons, About; updated, with why two labels were not enough.

Test plan

• Structural review of the component: Svelte block balance, tag nesting, every referenced constant declared, none left unused, no /about reference remaining, both icons imported and used on both surfaces.
• Confirmed About stays reachable: AppShell mounts AppFooter for both route groups, and the live footer markup (fetched from the running dev server) carries Platform → About → /about.
• Confirmed no e2e action navigates by the old labels: no clickLink in recipe.jsonl targets the nav entries; the only nav-label couplings in the suite were in 02-login, which this PR re-specifies.
• pnpm check / pnpm lint / pnpm test — not run: this host has no Node/pnpm toolchain and no Docker socket access, and standing up a second devcontainer was ruled out (1.9 GiB RAM, one vCPU, already running a stack). No type-level or branching logic was added — markup, class strings and two icon imports — so CI is the gate here.
• Eyeball at md and phone widths, and open the mobile panel (its hint text is the part no static check covers).

Noted, not touched (pre-existing)

tests/smoke/21-footer.spec.ts looks stale against the rebuilt footer (0265838), independent of this change: it matches a footer-wide About (now two links) and asserts a GitHub link the current footer deliberately does not render. Its own pass, not this one.