chore: update agent

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: be-marc

.agents/mlr3.md

@@ -81,6 +81,7 @@ Use structured error/warning functions from mlr3misc: `error_config()`, `error_i
 - New learners must pass `run_autotest()` and `run_paramtest()`.
 - Use shared assertion helpers: `expect_learner()`, `expect_task()`, `expect_resampling()`, `expect_measure()`, `expect_prediction()`.
 - Shared test infrastructure lives in `inst/testthat/` and is sourced by extension packages too.
+- Use `skip_if_not_installed(<package_name>)` to skip tests that require suggested packages.
 
 ### Documentation
 
@@ -97,6 +98,7 @@ Use structured error/warning functions from mlr3misc: `error_config()`, `error_i
 - Bibliographic references go in `R/bibentries.R` and are cited with `` `r format_bib("key")` ``.
 - Man page names for dictionary objects follow `mlr_learners_classif.rpart`, `mlr_tasks_iris`, etc.
 - When you write examples, make sure they work.
+- Wrap examples that use suggested packages in `if (mlr3misc::require_namespaces(<package_name>, quietly = TRUE)) {..}` blocks.
 
 ### `NEWS.md`