Shift+right-click in the viewport opens a cursor-anchored grid of snap
icons (names as hover tooltips). Picking one engages a one-shot
override: only that snap applies — even with running osnap off — until
the next point pick commits, which restores the saved configuration.
Esc drops an unconsumed override; an outside click closes the menu.
The status-bar snap toggles are untouched — this is a separate,
temporary mechanism.
Covers items 1 and 2 of #337 (mid-between-two-points still pending).
Co-Authored-By: Claude Fable 5 <[email protected]>