Checkpoint: Application complète de dématérialisation de facturation avec extraction IA (Mistral), authentification locale + Azure AD, stockage local, et export SFTP.

Fonctionnalités implémentées :
✅ Authentification locale (email/password) + Azure AD + Manus OAuth
✅ Upload drag-and-drop de fichiers PDF avec suivi en temps réel
✅ Extraction automatique avec Mistral AI (OCR + LLM)
✅ Détection de doublons (fournisseur, numéro, date)
✅ Score de qualité d'extraction (0-100)
✅ Tableau de bord avec statistiques
✅ Liste des factures avec recherche et filtres
✅ Paramètres utilisateur (LLM, keywords, SFTP)
✅ Historique des imports avec logs détaillés
✅ Gestion des utilisateurs (admin)
✅ Export SFTP manuel/automatique
✅ Stockage local avec organisation YYYY-MM
✅ Tests unitaires d'authentification

Architecture :
- Frontend : React 19 + Vite + TailwindCSS + Radix UI
- Backend : Express + tRPC + Drizzle ORM
- Base de données : MySQL (6 tables)
- IA : Mistral AI pour extraction
- Stockage : Local filesystem
- Export : SFTP

Pages :
- Login (choix local/Azure/Manus)
- Dashboard (statistiques)
- Upload (drag-and-drop)
- Invoices (liste avec recherche)
- Settings (LLM, keywords, SFTP)
- History (logs d'import)
- Users (gestion admin)

server/localStorage.ts

@@ -0,0 +1,111 @@
+import fs from "fs/promises";
+import path from "path";
+import { nanoid } from "nanoid";
+
+// Storage base path (local filesystem)
+const STORAGE_BASE_PATH = process.env.STORAGE_BASE_PATH || path.join(process.cwd(), "storage");
+
+/**
+ * Ensure storage directory exists
+ */
+async function ensureStorageDir(dirPath: string) {
+  try {
+    await fs.mkdir(dirPath, { recursive: true });
+  } catch (error) {
+    console.error(`[LocalStorage] Failed to create directory ${dirPath}:`, error);
+    throw error;
+  }
+}
+
+/**
+ * Generate a storage key with YYYY-MM prefix for organization
+ */
+export function generateStorageKey(userId: number, fileName: string): string {
+  const now = new Date();
+  const year = now.getFullYear();
+  const month = String(now.getMonth() + 1).padStart(2, "0");
+  const randomId = nanoid(8);
+  
+  // Format: YYYY-MM/userId-randomId-filename
+  return `${year}-${month}/${userId}-${randomId}-${fileName}`;
+}
+
+/**
+ * Store a file in local storage
+ * @param fileKey - Storage key (e.g., "2025-01/1-abc123-invoice.pdf")
+ * @param buffer - File content as Buffer
+ * @param contentType - MIME type (optional, for metadata)
+ * @returns Object with key and public URL
+ */
+export async function localStoragePut(
+  fileKey: string,
+  buffer: Buffer,
+  contentType?: string
+): Promise<{ key: string; url: string }> {
+  try {
+    const fullPath = path.join(STORAGE_BASE_PATH, fileKey);
+    const dirPath = path.dirname(fullPath);
+    
+    // Ensure directory exists
+    await ensureStorageDir(dirPath);
+    
+    // Write file
+    await fs.writeFile(fullPath, buffer);
+    
+    // Generate public URL (served by Express static middleware)
+    const url = `/storage/${fileKey}`;
+    
+    console.log(`[LocalStorage] File stored: ${fileKey}`);
+    
+    return { key: fileKey, url };
+  } catch (error) {
+    console.error(`[LocalStorage] Failed to store file ${fileKey}:`, error);
+    throw error;
+  }
+}
+
+/**
+ * Retrieve a file from local storage
+ * @param fileKey - Storage key
+ * @returns File content as Buffer
+ */
+export async function localStorageGet(fileKey: string): Promise<Buffer> {
+  try {
+    const fullPath = path.join(STORAGE_BASE_PATH, fileKey);
+    const buffer = await fs.readFile(fullPath);
+    return buffer;
+  } catch (error) {
+    console.error(`[LocalStorage] Failed to retrieve file ${fileKey}:`, error);
+    throw error;
+  }
+}
+
+/**
+ * Delete a file from local storage
+ * @param fileKey - Storage key
+ */
+export async function localStorageDelete(fileKey: string): Promise<void> {
+  try {
+    const fullPath = path.join(STORAGE_BASE_PATH, fileKey);
+    await fs.unlink(fullPath);
+    console.log(`[LocalStorage] File deleted: ${fileKey}`);
+  } catch (error) {
+    console.error(`[LocalStorage] Failed to delete file ${fileKey}:`, error);
+    throw error;
+  }
+}
+
+/**
+ * Check if a file exists in storage
+ * @param fileKey - Storage key
+ * @returns true if file exists, false otherwise
+ */
+export async function localStorageExists(fileKey: string): Promise<boolean> {
+  try {
+    const fullPath = path.join(STORAGE_BASE_PATH, fileKey);
+    await fs.access(fullPath);
+    return true;
+  } catch {
+    return false;
+  }
+}