chore: bump prime-sandboxes to 0.2.39

[mikasenghaas]

Summary

• Bump the prime-sandboxes pin from >=0.2.37 to >=0.2.39 and update the lockfile.
• The lock pulls in two new transitive dependencies of 0.2.39: protobuf-py and protobuf-py-ext.

Verification

• uv sync succeeds and import prime_sandboxes reports version 0.2.39.

🤖 Generated with Claude Code

Note

Bump prime-sandboxes dependency to >=0.2.39

Updates the version constraint in pyproject.toml and refreshes uv.lock accordingly.

^{Macroscope summarized 056461a.}

[mikasenghaas]

Closing for now — there is a regression in prime-sandboxes 0.2.39, so we cannot bump yet.