Introduce Import and Advanced Export Features

- Added `ImportBookForm` component for importing DOCX files with chapter selection and metadata customization.
- Implemented advanced export options (PDF, DOCX, EPUB) with `ExportSetting` component.
- Developed utility methods for transforming books into exportable formats in `Export.ts`.
- Expanded database models and repositories to support import/export functionality.
- Enhanced localization for import/export flows and updated UI components for improved user experience.

CLAUDE.md

@@ -0,0 +1,96 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+ERitors Scribe is an Electron + Next.js desktop application for writers. It uses SQLite with WASM for local storage, supports offline mode with PIN authentication, and encrypts user data with AES-256-CBC.
+
+## Commands
+
+```bash
+# Development (starts Next.js on port 4000 + Electron with hot reload)
+npm run dev
+
+# Build for specific platform
+npm run build:mac
+npm run build:win
+npm run build:linux
+npm run build:all
+```
+
+## Architecture
+
+### Process Model
+
+```
+Renderer (Next.js)  <--IPC-->  Main Process  <-->  SQLite DB
+       via window.electron.invoke()
+```
+
+- **Main process**: `electron/main.ts` - Window management, IPC handlers, OS integration
+- **Preload script**: `electron/preload.ts` - Secure contextBridge API
+- **Renderer**: Next.js App Router with static export (`output: 'export'`)
+
+### Key Directories
+
+- `electron/` - Main process code (IPC handlers, database, storage)
+- `electron/ipc/` - IPC handlers organized by domain (book, chapter, character, etc.)
+- `electron/database/` - SQLite service, models, repositories, encryption
+- `electron/storage/SecureStorage.ts` - OS-level secure storage (macOS Keychain, Windows DPAPI)
+- `app/` - Next.js pages (App Router)
+- `context/` - React contexts for state management (13+ contexts)
+- `components/` - React components
+- `lib/locales/` - i18n translations (fr.json, en.json)
+
+### IPC Handler Pattern
+
+All IPC handlers use `createHandler<TBody, TReturn>()` factory in `electron/database/LocalSystem.ts`:
+
+```typescript
+// electron/ipc/book.ipc.ts
+ipcMain.handle('db:book:books', createHandler<void, BookProps[]>(
+    async (userId, _body, lang) => Book.getBooks(userId, lang)
+));
+
+// Frontend usage
+const books = await window.electron.invoke('db:book:books');
+```
+
+The factory auto-injects `userId` and `lang` from secure storage, handles errors uniformly.
+
+### State Management
+
+Context-based architecture with providers:
+- `UserContext` - Authenticated user
+- `BookContext` - Current book
+- `OfflineContext` - Offline mode state
+- `SessionContext` - Session data
+- `LangContext` - i18n
+
+### Database
+
+- One SQLite file per user: `eritors-local-{userId}.db`
+- Uses `node-sqlite3-wasm` (WASM-based SQLite)
+- AES-256-CBC encryption for stored data
+- PBKDF2 key derivation (100K iterations)
+- Schema in `electron/database/schema.ts`
+
+### Security
+
+- `contextIsolation: true`, `nodeIntegration: false`, `sandbox: true`
+- OS-level secure storage for tokens and encryption keys
+- Per-user encryption keys stored in SecureStorage
+- Offline PIN hashed with bcrypt
+
+## TypeScript Configuration
+
+- `tsconfig.json` - Next.js/React (renderer)
+- `tsconfig.electron.json` - Electron main process
+- `tsconfig.preload.json` - Preload script
+
+## Build Output
+
+- `dist/` - Compiled TypeScript
+- `out/` - Next.js static export
+- `release/` - Electron builder output (DMG, NSIS, AppImage)