Frames the view deterministically: Scene now carries padded per-axis bounds
(opstool's pad_ratio 0.15, with unit slack on degenerate axes) plus
axis_overrides() pinning range + autorange=False, so the model is never
flush against the viewport edge. Adds entity hover templates (Node #n /
Element #n with an empty extra tag), and an optional axis outline (grid +
ticks) - off by default so the SAP2000-like clean viewport is unchanged;
the coloured X/Y/Z axis lines always stay as the orientation cue.
The outline is exposed as a bool in the Plot Properties table, so the
table-driven dialog now builds a checkbox for kind=bool.