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.tracks/leave.ludic

@@ -19,7 +19,7 @@ export function tracks_leave_at(kind: int, x: float, z: float, yaw: float, sp: i
   t.legend = legend
   t.made = made
   t.read = false
-  if tk_world != null and tk_world.placed != null { tk_world.placed(kind, i) }
+  TracksWorld.placed(kind, i)
   return i
 }