feat: complete Phase 1 infrastructure

- erp-core: error types, shared types, event bus, ErpModule trait
- erp-server: config loading, database/Redis connections, migrations
- erp-server/migration: tenants table with SeaORM
- apps/web: Vite + React 18 + TypeScript + Ant Design 5 + TailwindCSS
- Web frontend: main layout with sidebar, header, routing
- Docker: PostgreSQL 16 + Redis 7 development environment
- All workspace crates compile successfully (cargo check passes)

apps/web/src/stores/app.ts

@@ -0,0 +1,23 @@
+import { create } from 'zustand';
+
+interface AppState {
+  isLoggedIn: boolean;
+  tenantName: string;
+  theme: 'light' | 'dark';
+  sidebarCollapsed: boolean;
+  toggleSidebar: () => void;
+  setTheme: (theme: 'light' | 'dark') => void;
+  login: () => void;
+  logout: () => void;
+}
+
+export const useAppStore = create<AppState>((set) => ({
+  isLoggedIn: false,
+  tenantName: '',
+  theme: 'light',
+  sidebarCollapsed: false,
+  toggleSidebar: () => set((s) => ({ sidebarCollapsed: !s.sidebarCollapsed })),
+  setTheme: (theme) => set({ theme }),
+  login: () => set({ isLoggedIn: true }),
+  logout: () => set({ isLoggedIn: false }),
+}));