BlendFileBlock attributes:
Explicit annotation on BlendFileBlock are needed because otherwise
e.g. `block.add_old` type was imprecisely inferred from the
assignments as `int | Any`, where `Any` comes from `.unpack` returning
`tuple[Any, ...]`.
Ideally unpack should be somehow connected to the returned types, but
this solution should work for now just to avoid typing errors.
dna_io - add some missing annotations:
Some annotations were needed to ensure `block.code` will be inferred
as `bytes` and not `bytes | Unknown`.
Reviewed-on: https://projects.blender.org/blender/blender-asset-tracer/pulls/92897
Reviewed-by: Sybren A. Stüvel <sybren@blender.org>