Add wildcard peer listing and shell completion to the libby CLI

[mikelangmayr]

• libby list hsfei.% lists the live daemons in a group; libby list %.%.isconnected reads one keyword across the fleet. A % in the group or daemon segment is answered by broadcast
• Libby.broadcast_request collects replies to a destination-less REQ, which bamboo sends but never waits for
• Client.peers and Client.peer_listings expose the same broadcast programmatically; Client.list routes to it when the pattern spans daemons
• Only daemons are listed: every Libby serves keys.list, so LibbyDaemon builds its Libby with is_daemon=True and a reply counts only if it reports that
• libby completion bash|zsh prints shell code for TAB completion of verbs, flags and addresses, with candidates from the same broadcast, a 0.5s bound and a 10s cache in ~/.libby/completion_cache.json. Adds an argcomplete dependency
• README now points at this broadcast for finding peers and says plainly that discovery, meaning a peer table you can ask who is alive, is not implemented yet: peers_alive is always empty since Protocol never instantiates a PeerTable, ZMQ's hello only reaches peers already in the address book, and Libby.rabbitmq never starts hello
• These patterns always wait the full timeout, 1s by default, since nothing on the wire says how many daemons exist. Over ZMQ the broadcast reaches only the address book
• Peer listing cases run on both transports with three daemons across two groups plus a client posing as one; also verified by driving the real CLI and argcomplete's protocol against a live fleet on a local broker

[prkrtg]

With this change, I think we need to re-think a bit about "who" is replying back. Before with keys.list we are under the assumption that everyone is a daemon (and libby client is another daemon). I'm thinking when a Libby object is created, it now says whether it's is_daemon=True or not. Only LibbyDaemon instances sets that tag to True; regular Client connections default to False. When peer_listings() collects the broadcast replies, it now only keeps the ones where is_daemon=True.

[mikelangmayr]

Confirmed: a plain Client(self_id="hsfei.impostor") shows up in peers('hsfei.%').

Added is_daemon, set only by LibbyDaemon.build_libby and reported from keys.list. A reply is listed only if it reports the flag. Tested on both transports.