add EvalStatus enum

[peterj]

No description provided.

[krisztianfekete]

We have to change the protocol definition as well:

agentevals/src/agentevals/_protocol.py

Lines 65 to 74 in d826b9a

	class EvalResult(BaseModel):
	"""Output payload expected from a custom evaluator on stdout."""
	score: float = Field(ge=0.0, le=1.0)
	status: Optional[str] = Field(
	default=None,
	description='One of "PASSED", "FAILED", "NOT_EVALUATED". Derived from score vs threshold if omitted.',
	)
	per_invocation_scores: list[Optional[float]] = Field(default_factory=list)
	details: Optional[dict[str, Any]] = None