Extract build conditions, can't build 1 tile below gravity well, only gravity well can build at y==1, etc

[github-actions]

laputa/packages/client/src/game/systems/constructionSystem.tsx

Lines 9 to 14 in d118bea

	// TODO: Extract build conditions, can't build 1 tile below gravity well, only gravity well can build at y==1, etc
	const canBuildAtPosition = (position: Vector3) => {
	const {
	input: { building },
	} = getState();
	if (position.y < 0) return false;

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This issue was generated by todo-issue based on a TODO comment in d118bea. It's been assigned to @Cygnusfear because they committed the code.