Built-in "Module stats" widget — renders the get_config/0 map of any discovered PhoenixKit module, selected by its module_key setting.

Demonstrates the widget view + size contract: it renders a full key/value table in the "detailed" view and a single headline count in "compact", and it falls back to compact automatically when the instance is sized too small for a table (size.w < 3 or size.h < 2). It resolves the module through core's PhoenixKit.ModuleRegistry and degrades gracefully when core isn't loaded or the key is unknown. The settings form offers the installed modules as a SELECT (module_options/0) — nobody should have to know registry keys.