Reachability fix found during release-artifact verification: the help text,
`agentnode sandbox doctor` output, and CHANGELOG all tell users to run
`agentnode ...`, but the package only installed the `agentnode-sdk` console
script. A user doing `pip install agentnode-sdk` and then `agentnode sandbox
pull` (the key command to make the sandbox usable) would hit "command not found".

Add an `agentnode` console-script alias alongside `agentnode-sdk` (both point to
agentnode_sdk.cli.main:cli) so the documented commands actually work. Verified in
the rebuilt wheel: entry_points.txt lists both scripts; a fresh-venv install
provides `agentnode` and `agentnode-sdk`, both expose the sandbox subcommands.

Packaging metadata only — no code change. Non-API suite 2067 passed.