TASK.md

Task contract: validate untrusted transaction payload

Change only starter/validator.py.

• Implement validate_transaction_payload(raw: dict) -> tuple[bool, dict].
• Return (True, sanitized_dict) on success, or (False, errors_dict) on failure.
• Key normalization:
  • Support both userId and user_id -> output normalized user_id: int.
  • Support both amount as float/int or dirty currency string (e.g. "$120.50" or " 120.50 ") -> output amount: float rounded to 2 decimal places. Amount must be > 0.
  • status must be one of {"pending", "completed", "failed"} (case-insensitive) -> output lowercase string.
• If payload is missing required fields or has invalid values, populate errors_dict mapping field name to error message.
• Do not raise unhandled exceptions on malformed input.

Done means python examples/pydantic-validation/verify.py starter exits successfully.