M1 UI: shadcn + TeamUp design language

Initialize shadcn/ui (radix-nova, Tailwind v4) in client/ and rebuild the M1 interface
on the design language:
- Token layer recolored in index.css: light "calm command center" content surface,
  rationed indigo brand, the deep-indigo sidebar, the load-bearing seat-state triad
  (--color-seat-human slate / -open amber / -ai indigo) + teal "approved" / amber "held",
  Hanken Grotesk (variable) as the production font.
- App shell: deep-indigo sidebar (Board / Cartable / Org-chart-soon nav + sign out) on a
  light content area; StatusDot uses the seat-state tokens.
- LoginPage: Card-based sign-in / first-owner bootstrap, toast (sonner) errors.
- BoardPage: shadcn Card columns (backlog→in progress→in review→done), Badge task types,
  Select to move, Avatar/Assign-to-me, and the cartable panel — wired to the M1 API.
- Path alias @ -> src (tsconfig paths + vite); dropped baseUrl (deprecated in TS 6).

Components added via the shadcn CLI: button, card, badge, input, label, select,
separator, avatar, skeleton, sonner. Client `npm run build` is green (tsc + vite).
Still pending a live click-through.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/src/store/auth.ts

@@ -5,7 +5,8 @@ interface AuthState {
   token: string | null
   memberId: string | null
   organizationId: string | null
-  setAuth: (token: string, memberId: string, organizationId: string | null) => void
+  email: string | null
+  setAuth: (token: string, memberId: string, organizationId: string | null, email?: string | null) => void
   logout: () => void
 }
 
@@ -15,8 +16,10 @@ export const useAuth = create<AuthState>()(
       token: null,
       memberId: null,
       organizationId: null,
-      setAuth: (token, memberId, organizationId) => set({ token, memberId, organizationId }),
-      logout: () => set({ token: null, memberId: null, organizationId: null }),
+      email: null,
+      setAuth: (token, memberId, organizationId, email = null) =>
+        set({ token, memberId, organizationId, email }),
+      logout: () => set({ token: null, memberId: null, organizationId: null, email: null }),
     }),
     { name: 'teamup-auth' },
   ),