Graph-Based Layer System for Dynamic Cost Updates

[JustusBraun]

This PR replaces the layer management system with a dependency graph to model how data flows between layers.
The combination of cost layers is now handled using combination layers, which combine the cost maps of multiple input layers in different ways. The CombinationLayer replicates the weighted average used by the old layer system and the MaxCombinationLayer uses the maximum cost of a vertex across all input layers. The layer used for planning and control can be configured using the MeshMap's default_layer parameter. The costs are copied from the layer into the MeshMap's dense cost buffer to allow for async access and updates and constant time lookup of vertex costs.

[JustusBraun]

I forgot to mention that these changes require the MeshVertexCostsSparseStamped from mesh_tools/feature/dynamic-cost-updates, which is why the build failed.

[amock]

After resolving some of the remaining TODOs and getting the CI running again, this looks good to be merged into this repository’s feature branch. I would also suggest increasing the version of all packages to 2.1.0.

Since we have a lot of changes here, for the next step of merging into the main branch it would be good to have runtime tests. For example, a new tutorial package that uses the dynamic layer or something similar.

[JustusBraun]

Since this PR changes the AbstractLayer interface I agree that we should increase the version number.

Because we are already changing the interface I would suggest changing the AbstractLayer::costs() and AbstractLayer::lethals() methods to return const references to the respective data.
I don't see the need for external code to be able to change the costs or lethal vertices stored in a layer and as far is I know this is not used anywhere.

mesh_navigation/mesh_map/include/mesh_map/abstract_layer.h

Lines 96 to 108 in c6e4dc7

	/**
	* @brief Returns a vertex map, which associates a cost to each vertex handle.
	* If a vertex handle is not associated with a cost value, i.e. there is no value
	* in the map, the mesh_map will use the default value from threshold().
	* @return a vertex map containing floats.
	*/
	virtual lvr2::VertexMap<float>& costs() = 0;
	/**
	* @brief Returns a set of vertex handles which are associated with "lethal" obstacles.
	* @return set of vertex handles which are associated with lethal obstalces.
	*/
	virtual std::set<lvr2::VertexHandle>& lethals() = 0;

[amock]

I successfully tested this PR in combination with the "feature/dynamic-cost-updates" branch of the tutorials under Ubuntu 24 / ROS 2 Jazzy.