Add quantity stub file?

src/unxt/quantity.pyi

@@ -0,0 +1,41 @@
+from typing import Any, Generic, LiteralString, Self, TypeVar
+
+from quax import ArrayValue
+
+_T = TypeVar("_T", bound=LiteralString)
+
+class AbstractQuantity(ArrayValue):
+    # NumpyBinaryOpsMixin
+    def __add__(self, other: Any) -> Self: ...
+    def __radd__(self, other: Any) -> Self: ...
+    def __sub__(self, other: Any) -> Self: ...
+    def __rsub__(self, other: Any) -> Self: ...
+    def __mul__(self, other: Any) -> Self: ...
+    def __rmul__(self, other: Any) -> Self: ...
+    def __matmul__(self, other: Any) -> Self: ...
+    def __rmatmul__(self, other: Any) -> Self: ...
+    def __truediv__(self, other: Any) -> Self: ...
+    def __rtruediv__(self, other: Any) -> Self: ...
+    def __floordiv__(self, other: Any) -> Self: ...
+    def __rfloordiv__(self, other: Any) -> Self: ...
+    def __mod__(self, other: Any) -> Self: ...
+    def __rmod__(self, other: Any) -> Self: ...
+    def __pow__(self, other: Any) -> Self: ...
+    def __rpow__(self, other: Any) -> Self: ...
+
+    # NumpyUnaryMixin
+    def __neg__(self) -> Self: ...
+    def __pos__(self) -> Self: ...
+    def __abs__(self) -> Self: ...
+
+    # NumpyRoundMixin / TruncMixin / FloorMixin / CeilMixin
+    def __round__(self, ndigits: int = ...) -> Self: ...
+    def __trunc__(self) -> Self: ...
+    def __floor__(self) -> Self: ...
+    def __ceil__(self) -> Self: ...
+
+class AbstractParametricQuantity(AbstractQuantity, Generic[_T]):
+    @classmethod
+    def from_(cls, value: Any) -> Self: ...
+
+class Quantity(AbstractParametricQuantity[_T]): ...