The right-edge drag's growth was capped at the screen's visible frame,
because each snap tick grows the window; on a window near the screen edge
that left a lane stuck at a tick or two of headroom. Settled 2026-08-08
(03-board-ui.md § Lane, superseding the pathfinder's hard stop): at the
screen the window pins and each further tick re-divides the fixed strip
width across one more unit — siblings compress, the stepper's mechanism
arriving under the drag's fingers. The regimes meet with no pixel jump
(the re-divided standard at the fit IS the frozen standard, by the
exact-fill identity), shrinking mirrors the way back, the rubber band
moves to the strip's own capacity, and a window with no headroom at all —
full screen included — re-divides from the very first snap.
New pure arithmetic in LaneLayoutMath (pinnedStripWidth, resizeStandard,
resizeMaxUnits, resizeWindowDelta, snappedUnits over per-count slots);
LaneResizeSession splits the tick across the regimes and derives its
standard from the live count; the handle and BoardView hand the session
the strip's whole divide. 2709 unit tests green (+11).
Claude-Session: https://claude.ai/code/session_014PtZdPwqZuqEDLc6wZMtEy
LaneWidthHold: after the release the session's frozen standard and the
WRITTEN unit count keep governing the strip until a landed snapshot
carries that width back — dividing the already-grown window by the
stale unit total in between was the visible two-step. A deliberately
separate type from CommittedHold: that hold stands in for an
arrangement and any landing retires it; this one stands in for a value
and only a landing that carries it will do. Echo reads through
LaneLayoutMath.displayUnits so the width-1 key-removal case compares
right; the watch rides landedReloads so a value-equal echo still
answers; width writes now return whether bytes reached disk so a
refused or no-op write dissolves the hold instead of arming it; the
1500ms timeout family covers the rest.
Drag-perf card 231e3693.
Claude-Session: https://claude.ai/code/session_01CqjXB7ASoWtbyoGod68k97
rzen