refactor(packages): the mechanic packages use ludic_base only, and ask through ports

ludic.clock, .effects, .inventory, .wallet, .weather and .tracks say
'uses ludic_base' (ludic.base uses nothing). ClockWorld, PackRules,
WeatherWorld and TracksWorld are export ports whose defaults are the old
fallbacks; clock_bind, inv_bind, weather_bind and tracks_bind are gone,
and the tests bind their fakes. The base README's toy does the same.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ludic.inventory/tests/inventory_test.ludic

@@ -21,10 +21,9 @@ program InventoryTest {
     return k
   }
 
+  bind PackRules { stack_limit: fn limit }
+
   function fresh() -> void {
-    let r = new PackRules
-    r.stack_limit = fn limit
-    inv_bind(r)
     inv_config(names("wood", "rod", "fish"))
     inv_reset()
   }