Add a display-only `activity` field to AgentRef plus `setActivity`, fed
from the subagent progress chokepoint with a short gist of the agent's
latest intent (or current tool). Render it in the `irc list` output, the
subagent peer roster, and the TUI peer card, beside the role-derived
display name. setActivity emits no event — the roster reads on demand —
so the per-tool-call rate stays off the registry listener path. Peers
with no activity render without a dangling clause.
Refs #2470
Op: extend
Replaces the blocking auto-reply IRC turn with a process-global IrcBus and a four-op tool (send/wait/inbox/list). send is fire-and-forget with per-recipient delivery receipts (injected/woken/revived/failed); replies become real turns by the recipient, observed via wait (or the send await:true sugar). Bounded per-agent mailboxes (cap 100) drop oldest on overflow; AgentSession.deliverIrcMessage folds an in-flight delivery in as a non-interrupting aside at the next step boundary, or starts a real wake turn when idle. AgentRegistry/lifecycle handle the idle→woken / parked→revived transitions, so messaging a non-running peer brings it back. Adds a dedicated TUI renderer (directional headers, delivery-outcome coloring, quoted bodies, per-recipient receipt trees, status-badged peer lists with unread counts). irc.timeoutMs is now the default timeout for wait / send await:true. AgentSession sheds the agentRegistry config field, the dedupeIrcReply → dedupeEphemeralReply rename (now used by /btw and /omfg), and the background-channel exchange queue / forwardIrcRelayToMain plumbing the auto-reply model needed.
metaphorics