Single command for both first install and subsequent updates:
curl -sSf https://git.naps.pt/naps62/maestro/raw/branch/main/install.sh | sh
Builds `maestro-installer` into a temp `--root`, runs the wizard, cleans up —
so only `maestrod` and `maestro` persist in `~/.cargo/bin`. Re-running updates
in place via cargo install's overwrite semantics. Wizard flags pass through
with `sh -s --`. Docs updated to lead with the one-liner.
Refs NAP-225.
