Stage 1 substrate for the bottom-panel arc (docs/bottom-panel-framing.md).
- `WindowParams` (side / fixed_rows / dedicated + implementation-owned
quit action and remembered document origin), `Side`, `QuitAction` with
a bounded replacement history, and the `MIN_WINDOW_OUTER_ROWS` floor.
- `Layout::compute(area, fixed)` allocates fixed rows before dividing the
remainder by weight; both production callers feed the same shared map,
including the peer-presence overlay pass that derives its own rect.
- `subtree_min_rows` / `interactive_min_rows`: the recursive minima, and
`boundary_below` for the shared drag / keyboard resize boundary rule.
- `FrontendView` gains `panel_capable`, `frame_geometry`, and the derived
`panel_hidden`, each spelled explicitly at every construction site.
- `EditorCore`: `primary_document_window`, the non-side target rule,
`display_buffer` + placement policy, `quit_window`, side-window removal
on `kill_buffer`, per-frontend jump entries with origin windows, and the
shared resolve/load-without-switch seam the initial-target bootstrap now
uses too.
- `EditorState`: the panel reconciliation transaction, geometry
declaration, the side-window `dispatch_idle_for` gate, divider paint,
and divider drag.
- `pmacs.window.display / display_file / quit / panel / params /
set_params / resize / display_target`, plus `builtin/runtime/window.lua`
with `window.panel-height`, `window.min-height`, and the resize commands.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
