feat: full book management system with backend API, frontend UI, and spec docs

- Backend: Book model with reading progress, DRF ViewSet with full CRUD,
  search, sort, filter, pagination, mark-as-finished, stats endpoint
- Frontend: Library grid, BookCard, BookDetail, BookForm components with
  React 19 + TypeScript + Vite
- Tests: 29 passing tests covering models, API, serializers, permissions
- Spec: backend api-spec.md and frontend component-spec.md in docs/

Closes crisleo-hermes/cloud-reader#3

package.json

@@ -0,0 +1,14 @@
+{
+  "name": "cloud-reader",
+  "version": "1.0.0",
+  "private": true,
+  "workspaces": [
+    "frontend",
+    "shared"
+  ],
+  "scripts": {
+    "frontend": "yarn workspace frontend dev",
+    "backend": "cd backend && python manage.py runserver",
+    "build": "yarn workspace frontend build"
+  }
+}