Lay the Almanacka design foundation: tokens, type, shell

New token system in global.css (near-white surfaces, one ink-blue
accent, no sub-12px type), self-hosted Schibsted Grotesk, rewritten
primitives (buttons, fields, modal shell, segmented, disclosure,
skeleton), a borderless 56px header with an SV | EN language toggle,
an Icon component replacing glyphs, page skeletons that keep the
layout during loading, and leave-type colours moved out of TS into
CSS variables. Feature blocks keep their structure for later phases.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

frontend/src/pages/Calendar.test.tsx

@@ -71,10 +71,6 @@ vi.mock('@/components/layout/Layout', () => ({
   Layout: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
 }))
 
-vi.mock('@/components/common/LoadingSpinner', () => ({
-  LoadingSpinner: () => <div>Loading...</div>,
-}))
-
 vi.mock('@/components/modals/PlannedDayModal', () => ({
   // Exposes the props this test suite cares about as data attributes/buttons
   // so tests can assert on Calendar.tsx's wiring without rendering the real
@@ -313,7 +309,7 @@ describe('Calendar', () => {
     vi.mocked(useWorkspace).mockReturnValue({ ...mockWorkspace, isLoading: true })
 
     render(<Calendar />)
-    expect(screen.getByText('Loading...')).toBeInTheDocument()
+    expect(screen.getByTestId('page-skeleton')).toBeInTheDocument()
   })
 
   it('renders 7 weekday headers in Monday-first Swedish order', () => {