Writes the admin-area naming options into the host's config/config.exs, commented out.

Why a comment block rather than a doc link

:admin_panel_label takes one of a closed set of preset atoms (PhoenixKit.Config.admin_label_presets/0). A developer cannot guess that vocabulary, and the two places it was written down — the settings page and the CHANGELOG — are not where anyone stands when they go to change it. The admin settings page can now simply say "set it in config.exs", because the list is waiting there when they arrive.

Every line is a comment, so the block is inert: it cannot change behaviour, cannot conflict with anything the host writes, and does not care where in the file it lands. That is what makes appending safe even after import_config.

Idempotent via @marker — mix phoenix_kit.update runs this too, so a host that installed before this existed picks the block up, and one that already has it (or has deleted it on purpose) is left alone.