Smart Expense Extractor API
Base: POST /api/extract
Headers: x-extractor-key:<sk_...>
Body: multipart/form-data; file=<file>
Res: {"success":true,"data":{"supplierName":"","vatNumber":"","expenseDate":"YYYY-MM-DD","amountExclVat":0,"vatRate":0,"totalAmount":0,"category":""},"metadata":{"stepUsed":"","hasTextLayer":true},"confidence":{"overall":0}}

Auth Routes (Dashboard):
POST /api/auth/login, POST /api/auth/register, POST /api/auth/logout, GET /api/auth/me

API Keys (Require Auth):
POST /api/keys
Res: {"id":"","name":"","apiKey":"sk_...","createdAt":""}
DELETE /api/keys/:id
GET /api/keys/stats
PUT /api/keys/alerts/webhook
Body: {"endpointUrl":"","enabled":true,"dailyRequestThreshold":1000,"timeoutMs":5000,"signingSecret":""}