feat(projects): section headings you can count at a glance, and an Inbox that speaks the language

Two from use.

Section headings were small uppercase text over a hairline — a heading you have to
look for. A project with four sections is four groups, and the eye should be able
to count them without reading a word, so the heading gets a ground of its own and
the rows sit against the page. `--surface` rather than a tint of the accent: the
colour on that page belongs to the project, and a section is not a second thing to
colour. A step in lightness separates them in all five themes without anybody
measuring anything.

And the Inbox. The server names it at account creation, before anybody has seen a
settings page, so it is the one project name nobody chose — and an account made in
Danish went on saying "Indbakke" inside an English interface, which reads as a
string somebody forgot to translate. It was. `projectName()` translates it while it
still carries the name the server gave it; rename it and that is your name for it,
in every language, like any other project. The rename field keeps the raw name, or
editing a translated label would save the translation.

The screenshot set gains the list view, which is where sections read as bands
rather than as columns — and the shape most people actually work in.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

web/src/routes/gruppe/[id]/+page.svelte

@@ -13,7 +13,7 @@
 	 */
 	import { page } from '$app/stores';
 	import { api, humanMessage } from '$lib/api.js';
-	import { app } from '$lib/stores.svelte.js';
+	import { app, projectName } from '$lib/stores.svelte.js';
 	import { colorVar } from '$lib/colors.js';
 	import { focusOnMount } from '$lib/focus.js';
 	import { t } from '$lib/i18n.svelte.js';
@@ -165,7 +165,7 @@
 							<a href="/projekt/{project.id}">
 								<span class="dot" style="background: {colorVar(project.color)}" aria-hidden="true"
 								></span>
-								{project.name}
+								{projectName(project)}
 								<!-- Counted by the server in the same request. Open tasks, not all
 								     of them: "12" beside a project finished last year is a number
 								     that means nothing. -->