CLI polish: -v version alias and per-subcommand help

[arcaven]

Two discoverability nits from the round-2 pilot addendum (ArcavenAE/aae-orc#128):

• `sideshow -v` prints "unknown command: -v" while `--version`, `-V`, `-h`, `--help` all work. One-line alias.
• `sideshow enable --help` and `sideshow help enable` both print the full top-level usage dump. The flags that matter per verb (`--scope`, `--override-stale-lock`, `--allow-version-change`) are discoverable only via the runbook or the full dump — which is part of how the round-1 D9 bite happened (the escape hatch existed and nothing at the point of need surfaced it).

Per-subcommand help can stay minimal: the verb's usage line plus its flags.