feat(chunk): Add attachments to profile chunks

[markushi]

Adds a generic attachments list to profile chunks, exposed through the Python API. Each attachment references a file stored in the object store — e.g. a raw perfetto trace kept alongside the Sentry-processed chunk — with a name, an optional content_type, and a stored_id:

chunk.set_attachments([vroomrs.Attachment("raw_profile", "application/x-perfetto", "aef123345")])
chunk.get_attachments()  # -> list[Attachment]

New Attachment pyclass plus get_attachments / set_attachments on ProfileChunk, with matching .pyi stubs. The references survive compress() → decompress_profile_chunk(), i.e. they persist into the stored chunk representation (covered by a test mirroring the sentry writer flow).

Design notes for reviewers:

• Attachments are sample-v2-only: the getter returns an empty list and the setter is a no-op on legacy Android-format chunks.
• set_attachments replaces the whole list rather than appending, so it stays idempotent if the processing task retries.
• This PR also routes android profiles that carry a version through sample-format detection (from_json_vec_and_platform → version-based dispatch), so android sample-v2 chunks are no longer misrouted to the legacy Android format. This is required for android sample-v2 chunks to support attachments at all.

This is the writer/in-process half of the cross-repo feature; the Go read path lives in getsentry/vroom#670 and the kafka message contract in sentry-kafka-schemas. Needs a vroomrs release + pin bump in sentry once it lands.