- pkg/calc: DriveForSpeed treats restMass==0 as a valid ceiling-only
case (every positive drive solves it), so locking the displayed
speed of a D=1, W=A=S=C=0 ship is no longer a phantom "infeasible".
- ship-design-area: drive/weapons/shields/cargo inputs use a JS-driven
smart step on ArrowUp/ArrowDown (0↔1 jump, otherwise ±0.1) and hide
the native spinner so it cannot produce invalid (0, 1) values;
armament keeps its native step 1.
- Tech and planet MAT cells follow the same lock idiom as goal-seek
locks: open padlock (🔓) over the inherited value → click to open
an input with a closed padlock (🔒). The padlock slot is always
reserved, so the column width is stable.
- Tech overrides (design area and modernization target) are floored
at the player's current tech on this turn — a lower value is
flagged as invalid.
Ilia Denisov
e9b904332e