PRD 0019 chunk 2. The TUI's main render now draws two panes:
proposals on top (existing), active agents on the bottom (new).
Header counts both totals. The agents pane refreshes on the
same 1s tick — agents starting/stopping reflect without
operator action.
Each agent row shows slug, agent name, started-time (HH:MM:SS
of the metadata.json timestamp), and the bracketed list of
sidecars currently up. The `agent` service is filtered out of
the displayed list — it's always present so it'd be noise; the
sidecars are the differentiator. A bottle whose only running
service is `agent` (sidecars still warming up) renders as
`(starting)`.
No selection model yet — that's chunk 3. The cursor stays in
the proposals pane; `j/k`/arrow nav and the proposal action
keys are unchanged.