M1: minimal board UI (login, board, cartable)

A functional React/Vite SPA exercising the M1 API end-to-end:
- Zustand auth store (persisted JWT) + a small fetch client that attaches the bearer
  token and logs out on 401.
- LoginPage: sign in, or bootstrap the first owner on first run.
- BoardPage: set org name, create/select a team, create tasks, move them across the
  backlog -> in progress -> in review -> done columns, assign to me, and a cartable panel.
- React Router guards routes on the presence of a token.

Mirrors the integration-tested API contracts exactly. Compiles clean (tsc + vite);
still needs a manual click-through (run the web host + Postgres, or `docker compose up
--build`). dnd-kit drag, TanStack Query, and an orval-generated typed client are M1+
polish — buttons/selects drive task moves for now.

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

client/src/store/auth.ts

@@ -0,0 +1,23 @@
+import { create } from 'zustand'
+import { persist } from 'zustand/middleware'
+
+interface AuthState {
+  token: string | null
+  memberId: string | null
+  organizationId: string | null
+  setAuth: (token: string, memberId: string, organizationId: string | null) => void
+  logout: () => void
+}
+
+export const useAuth = create<AuthState>()(
+  persist(
+    (set) => ({
+      token: null,
+      memberId: null,
+      organizationId: null,
+      setAuth: (token, memberId, organizationId) => set({ token, memberId, organizationId }),
+      logout: () => set({ token: null, memberId: null, organizationId: null }),
+    }),
+    { name: 'teamup-auth' },
+  ),
+)