c.haven_labelled_defined: Combine defined vectors with metadata checks
Description
The c() method for defined vectors ensures that all semantic metadata
(label, unit, concept, namespace, and value labels) match exactly. This
prevents accidental loss or mixing of incompatible definitions during
concatenation.
Usage
# S3 method for haven_labelled_defined
c(...)
Value
A single defined vector with concatenated values and retained
metadata.