Wrapper around the tailscale command-line interface.
The local node is driven through its CLI rather than through the LocalAPI socket (ADR-0001), so this crate is where every one of those decisions lives: where the binary is found, what environment it inherits, how long it is given, how a secret reaches it without passing through the argument list, and which calls may overlap.
Everything above this crate sees [LocalBackend], a one-method trait, so
the server can be built over a fake in tests without spawning anything.