Look at the image. Is this a Bulgarian fiscal cash register receipt (касова бележка / фискален бон)?

Answer with ONLY valid JSON. No markdown. No extra text.

{
    "is_fiscal_receipt": true or false,
    "message": "string|null"
}

Rules:
- is_fiscal_receipt: true only if the image clearly shows a fiscal receipt (printed slip with fiscal data, not a product photo, invoice PDF screenshot, bank slip, menu, etc.)
- message: if is_fiscal_receipt is false, a short explanation in Bulgarian for the user; otherwise null