Bottom-panel Stage 2B-2, first half: the daemon-side primitives the
panel producer needs.
`GeometryUpdate` is three-valued rather than a boolean because the
caller must act differently on each arm. `declare_frame_geometry` stays
the grid/LOCAL allocator, keeps value dedup, and moves from
`saturating_add` to checked allocation with a fail-closed exhaustion
arm: it clears the declaration back to unknown, which is already
non-presentable, so reconciliation hides the panel rather than painting
one sized to a frame that no longer exists.
`accept_frame_geometry` is the separate semantic path. No value dedup —
a font or scale change can invalidate a panel frame while `CellSize` is
identical, which is exactly what daemon-side dedup cannot see (Q#BP2S1)
— and a lower epoch is rejected even when it carries identical data.
`panel_grid_size` derives Q#BP15a's third geometry: full declared
width, `fixed_rows` clamped by the recursive document minimum and then
by the shared wire area budget, with the stored request left alone.
`prepare_panel_projection` paints the side window through the Stage 2A
extracted painter, gating folds on the OWNING frontend rather than
`fold_map_for_window`'s active-frontend gate (Q#BP17), and takes the
side window's statusline segments as a parameter so one provider
invocation serves both surfaces. `window_cursor_cell` is `paint_frame`'s
caret derivation lifted out so the band does not become a second,
drifting copy of it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Lv428Fth9LRtffwJSsqH7T
Levi Neuwirth
81f54e23a9