feat: rizome sandbox

[samjtro]

cmd: rizome sandbox add
desc: adds either a local or remote sandbox by using the URI of the container. this is in the context of being able to add sandboxes to various code agents, both CLI (Claude Code, etc.) or IDE (Cursor, Windsurf).
optional flags: --uri, --provider, --name, --desc

cmd: rizome sandbox list
desc: lists all configured sandboxes

cmd: rizome sandbox update
desc: update a sandbox
optional flags: --name

all commands should be interactive by default utilizing our robust standard tui pkg