Closes the #3110 split — lib.rs is now just the crate doc comment and
the pub mod list.
journal.rs's new doc comment fixes a pre-existing bug: the old
JournalPriority doc text in lib.rs was actually half Capability's doc
(a leftover from an earlier reorder that moved the code but not the
comment above it).
Adds a real MCP-side path for the workaround #2639 documented: dial the
in-container HIVE_AGENT_SOCKET directly from cancel_loose_end (kind:"todo")
instead of shelling out via a tracked bash task (nc -U ...), which is what
was spawning a fresh completion todo on every clear and cascading forever.
hive-agent-mcp/src/mcp/render.rs: renamed local_todos's socket-dial guts
into a shared dial_agent_socket(req) helper, added mark_local_todo_done(id)
on top of it (MarkTodoDone request already existed server-side, unused
until now). mod.rs wires kind:"todo" into cancel_loose_end ahead of the
question/reminder/approval parse. args.rs + render.rs + docs/tools/bash.md
text updated to point at the new path instead of the old raw nc invocation.
