CommandService.execute appends the log-only pair around every resolved
handler — run before invocation, done at settlement, including thrown and
aborted handlers (kind:'error'); admission misses log nothing. commandId is
minted monotonically per instance; per-session appends serialize through a
tail queue over SessionStore.appendOutOfBand (zero-step wrap on an idle log,
direct join inside an open turn). The invariant companion now asserts the
pairing relation (unique run ids; a done requires a prior in-log run).
CommandSource is a minimal merge-extensible map (user variant only).
Dependent benches mount SessionStore; TUI/e2e snapshots re-recorded for the
executor's durable-append timing and the /status event counts.
Add a branded AgentMessageId assigned to each accepted send message and
returned from send/followup/steer/inject (was void). Rename the inbox
event payload InboxItemInfo to AgentMessage, carrying that id so a caller
can correlate a queued item with its enqueue/dequeue/discard events.
Replace send/steer/inject with one Agent.send primitive over the
(target × wakeup) matrix; followup/steer/inject become fixed-preset
alias methods on the now-abstract Agent class. Coalesce context/message
into user/message (injected context is a non-user source). Replace
agent/queued with agent/inbox/enqueue/dequeue/discard, add cancel
keepInbox, and add a FIFO-conservation invariant.
