Add foundational API client, UI components, and state management setup

- Created `generate-api-client.sh` for OpenAPI-based TypeScript client generation.
- Added `src/lib/api` with Axios-based API client, error handling utilities, and placeholder for generated types.
- Implemented Zustand-based `authStore` for user authentication and token management.
- Integrated reusable UI components (e.g., `Dialog`, `Select`, `Textarea`, `Sheet`, `Separator`, `Checkbox`) using Radix UI and utility functions.
- Established groundwork for client-server integration, state management, and modular UI development.

frontend/package.json

@@ -25,6 +25,7 @@
     "@radix-ui/react-checkbox": "^1.3.3",
     "@radix-ui/react-dialog": "^1.1.15",
     "@radix-ui/react-dropdown-menu": "^2.1.16",
+    "@radix-ui/react-icons": "^1.3.2",
     "@radix-ui/react-label": "^2.1.7",
     "@radix-ui/react-popover": "^1.1.15",
     "@radix-ui/react-select": "^2.2.6",
@@ -33,6 +34,7 @@
     "@radix-ui/react-tabs": "^1.1.13",
     "@tanstack/react-query": "^5.90.5",
     "axios": "^1.13.1",
+    "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "date-fns": "^4.1.0",
     "lucide-react": "^0.552.0",