feat: add Buchhaltung module with fiscal years, budget accounts, transactions, and approval workflow

backend/src/middleware/upload.ts

@@ -132,4 +132,42 @@ const issueOptions: any = {
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 export const uploadIssue: any = multer(issueOptions);
 
-export { UPLOAD_DIR, THUMBNAIL_DIR, WARTUNG_DIR, ISSUE_DIR };
+// ── Buchhaltung uploads (accounting receipts / Belege) ───────────────────────
+
+const BUCHHALTUNG_DIR = path.join(APP_ROOT, 'uploads', 'buchhaltung');
+try {
+  if (!fs.existsSync(BUCHHALTUNG_DIR)) {
+    fs.mkdirSync(BUCHHALTUNG_DIR, { recursive: true });
+  }
+} catch (err) {
+  logger.warn(`Could not create buchhaltung upload directory`, { err });
+}
+
+const buchhaltungStorage = multer.diskStorage({
+  destination(_req: any, _file: any, cb: any) {
+    cb(null, BUCHHALTUNG_DIR);
+  },
+  filename(_req: any, file: any, cb: any) {
+    const uniqueSuffix = `${Date.now()}-${Math.round(Math.random() * 1e9)}`;
+    const ext = path.extname(file.originalname);
+    cb(null, `${uniqueSuffix}${ext}`);
+  },
+});
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+const buchhaltungOptions: any = {
+  storage: buchhaltungStorage,
+  fileFilter(_req: any, file: any, cb: any) {
+    if (ALLOWED_TYPES.includes(file.mimetype)) {
+      cb(null, true);
+    } else {
+      cb(new Error(`Dateityp ${file.mimetype} ist nicht erlaubt.`));
+    }
+  },
+  limits: { fileSize: 20 * 1024 * 1024 },
+};
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export const uploadBuchhaltung: any = multer(buchhaltungOptions);
+
+export { UPLOAD_DIR, THUMBNAIL_DIR, WARTUNG_DIR, ISSUE_DIR, BUCHHALTUNG_DIR };