Bevy collection loop (docs-first stub)

Not a full port. Docs-first stub. Godot counterpart: godot-game-loop-collection.

When to use

Load this when the run is about picking up objects and reaching a count.

ECS shape

• Components: a collected flag and a quota resource you define.
• Resources: run-wide tables live in a resource (bevy-data-resources), not an autoload.
• Systems: mutate those components on Update or the fixed timestep. Use .chain() when damage must land before death.
• Messages: one-shot facts (hit, pickup, quest advance) go through bevy-events-messaging. This file does not add a new event type name.

Godot idea to Bevy idiom