PRD 0019 chunk 3. The TUI now has two focusable panes — proposals
and agents — and `Tab` toggles which one the `j/k`/arrow keys
move through.
Each pane keeps its own selection index. Switching panes doesn't
lose the position in the other; the cursor (`>` + reverse-video
row) appears only in the focused pane. The label line on each
pane shows "(focused)" when active.
Footer reshuffled: `[Tab] switch pane [j/k] move [Enter] view
[a/m/r] proposal [e/p] edit [q] quit`. When the agents pane is
focused and there's no status message to display, the idle
status line surfaces the currently-selected agent (or "[no
active agents]" / "[no agent selected]" fallbacks) so the
operator knows what an agent-scoped edit verb will target after
chunk 4 wires them up.
Proposal action keys (a/m/r/Enter) are gated on the proposals
pane being focused — pressing them with the agents pane focused
is a no-op. e/p still use the global discover-and-prompt flow
for one more chunk; chunk 4 swaps them to read the agents-pane
selection.
didericis