Prints a one-line header naming the estimator, then the data.frame.
The full human-readable view (per-cluster stats, profiles, OR/test
tables) was already printed by summary() when this object was
produced, so this method intentionally stays minimal to avoid
duplication. Auto-prints when the user types the variable at the REPL.
Usage
# S3 method for class 'tidy_covariates'
print(x, ...)