* Previously, deserializing an empty vector used `Vec::new()`, resulting
in zero capacity, which is not guaranteed to be aligned for `f32`/`f64`.
This could lead to undefined behavior when interpreting the data.
* We also inconsistently treated empty input: `"[]"` (text) was accepted
as a zero-length vector, but empty blobs (`&[]`) were rejected.
* Now:
* We initialize empty vectors with at least one element’s capacity to
preserve alignment.
* We allow zero-sized blobs and treat them the same as `"[]""` input
as empty vectors.
Closes#2371
e1dd028136