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/e2e/smoke.spec.js

@@ -1157,8 +1157,13 @@ test('kontoens sprog skifter hele fladen, ikke kun parseren', async ({ page }) =
 		/januar|februar|marts|maj|juni|juli|oktober|december/i
 	);
 
-	// The Inbox keeps its name: it is a project row created at signup, not a
-	// string in the interface, and the person can rename it like any other.
+	// The Inbox is named by the server at account creation, before anybody has seen
+	// a settings page — so it is the one project name nobody chose, and it follows
+	// the language like a label. Rename it and that becomes your name for it in
+	// every language, the same rule as any other project.
+	await expect(
+		page.getByRole('navigation', { name: 'Main menu' }).getByRole('link', { name: 'Inbox' })
+	).toBeVisible();
 
 	// Danish again, for everything that runs after this.
 	await page.goto('/indstillinger');