bump: minor
type: feat
Optional world boundaries (#84) — declare a single `Bounds` config entity (a rect `x, y, w, h` plus a policy, shipped from **ludic.core**) and the engine-owned world-bounds system keeps every moving `Body` inside the play area each frame, so a game no longer hand-clamps `Position`. Four policies: `0` clamp (walls), `1` wrap (toroidal), `2` bounce (clamp + flip the Body velocity on the axis that hit), `3` kill (despawn a body fully outside). It reads each body's `Collider` size so the whole box stays inside; off by default (no `Bounds` entity = open world). Registered on the engine-system registry for LateUpdate (after movement integrates) and spliced only when a game declares `Bounds`, so a game that never does compiles byte-identically. Also adds `World.despawn(entity)` — the reflective, by-id form of the `despawn` statement (runs `@OnDespawn` + frees the slot), which the kill policy uses and any system can call. Example: `examples/library/world_bounds.ludic`.