Class URVariable

Legacy variable class used for discovering variables in tree node parameters.

REPLACEMENT: Use the variable interfaces exported from @universal-robots/contribution-api/types/symbols:

• VariableDeclaration to represent a declared variable
• VariableReference to reference an existing variable
• VariableDescription (and VariableDescriptionWithReference) for UI/state consumption The allowed value types are now enumerated by VARIABLE_VALUE_TYPES instead of VariableValueType.

MIGRATION AID: To convert legacy URVariable objects to the new model, invoke the variable upgrade endpoint (upgradeURVariable). It returns either an existing VariableDescriptionWithReference for variable references, or a new VariableDeclaration for variable declarations.