@dataclass
class Seed:
    """A short prompt you maintain by hand."""

    id: str
    body: str
    title: str = ""
    targets: list[str] = field(default_factory=list)
    tags: list[str] = field(default_factory=list)
    category: str = ""
    pinned: bool = False
    path: Path | None = None

    @property
    def hash(self) -> str:
        """Only the body decides staleness — pinning or retitling must not
        invalidate a render that is still correct."""
        return digest(self.body)

    @classmethod
    def load(cls, path: Path) -> "Seed":
        meta, body = _split(path.read_text(encoding="utf-8"), path.name)
        if not body:
            raise FormatError(f"{path.name}: seed body is empty")
        return cls(
            id=meta.get("id") or path.stem,
            body=body,
            title=meta.get("title", ""),
            targets=list(meta.get("targets", [])),
            tags=list(meta.get("tags", [])),
            category=meta.get("category", ""),
            pinned=bool(meta.get("pinned", False)),
            path=path,
        )

    def write(self, path: Path) -> None:
@dataclass
class Render:
    """A seed expanded for one target model."""