`linkage_method()` parameter incorrectly labeled as "activation" in grid functions

[dnldelarosa]

The linkage_method() parameter function in tidyclust incorrectly labels the parameter as "activation" instead of "linkage_method" when used in grid creation functions like grid_regular().

Root Cause

File: R/dials-params.R
Line: 38

The linkage_method() function has a hardcoded label name:

linkage_method <- function(values = values_linkage_method) {
  dials::new_qual_param(
    type = "character",
    values = values,
    label = c(activation = "Linkage Method"),  # ← Should be "linkage_method"
    finalize = NULL
  )
}

Fix

Change line 38 from:

label = c(activation = "Linkage Method"),

To:

label = c(linkage_method = "Linkage Method"),

Impact

This forces users to manually rename the column with rename(linkage_method = activation) before using it with tune_cluster(), as shown in the current documentation and tutorials.

Reproducible Example

library(dials)
library(tidyclust)

# Current behavior - creates "activation" column instead of "linkage_method"
grid_regular(
  num_clusters(range = c(2, 4)),
  linkage_method(values = c("complete", "average", "ward.D2")),
  levels = c(3, 3)
)
#> # A tibble: 9 × 2
#>   num_clusters activation
#>          <int> <chr>     
#> 1            2 complete  
#> 2            3 complete  
#> 3            4 complete  
#> # ... with 6 more rows

After the fix, it should produce:

#> # A tibble: 9 × 2
#>   num_clusters linkage_method
#>          <int> <chr>         
#> 1            2 complete      
#> 2            3 complete      
#> 3            4 complete      
#> # ... with 6 more rows