When the Desktop has a bot's "Bot Chat" open, that session holds the
single-owner lease, so the `hermes -p <bot> chat -c "Bot Chat"` subprocess
`bot_relay.deliver` spawns refuses with "already has a live owner" and the
DM payload is dropped — the sender was already acked.
bot_relay.deliver now looks up a live in-process session for the target
profile whose title resolves to "Bot Chat" (same profile_home match as
session.resume's _find_live_unpersisted, pending_title for lazy sessions,
otherwise the db title) and, when found, submits the message through the
existing prompt.submit handler — the composer's choke point — so it lands
as a normal user turn (role alternation preserved, streams to the open
window). No live owner → the subprocess path runs exactly as before.
On the local message_agent subprocess path, the lease refusal is surfaced
as a structured `target_busy` delivery failure telling the sender the
message was NOT delivered, instead of a raw exit-1 with the text buried
in stderr.
Closes#100523
Supersedes #100544, #100542
Co-authored-by: fangliquanflq <fangliquan@qq.com>
Co-authored-by: 686f6c61 <github@00b.tech>
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