Add/suppress/clear one coded diagnosis on the current selection —
validates key against TOOTH_LEVEL_DX_KEYS and mode against
VALID_DX_OVERRIDE_VALUE (or null, which clears any existing
override for key); anything else is a silent no-op. Routed through
gateToothEditBatch directly (not applyToSelected) since
dxOverrides has no SVG/DOM side effect to re-render per tooth.
Add/suppress/clear one coded diagnosis on the current selection — validates
keyagainst TOOTH_LEVEL_DX_KEYS andmodeagainst VALID_DX_OVERRIDE_VALUE (ornull, which clears any existing override forkey); anything else is a silent no-op. Routed throughgateToothEditBatchdirectly (notapplyToSelected) sincedxOverrideshas no SVG/DOM side effect to re-render per tooth.