Volume meshing

[Alberto-o]

No description provided.

[Alberto-o]

Initially I wanted to make "isVolume" a property of the mesh, and not of the options. However, the mesh is passed as an arguments a lot of times, and I thought that having to copy a new property when creating derived meshes was error-prone. Options are not modified after being passed to the mesher, and there the flag for volume filling is conserved along the process

[Alberto-o]

Additionally: I see there is the option "volumeGroups". However, the StaircaseMesher seems to be meant to work with a surface mesh as input. I have preferred keeping the mesher initialization almost the same, and instead checking during the "process" step whether the body should be treated as a volume

[Alberto-o]

@copilot check the action log and propose a solution to fix the vcpkg related compilation issue

[Copilot]

@copilot check the action log and propose a solution to fix the vcpkg related compilation issue

I checked the failed Actions runs (dev had no relevant failures; feature/volume_mesh failed in all build matrix jobs). Root cause was vcpkg trying to use the GHA binary source (x-gha) and failing with missing ACTIONS_RUNTIME_TOKEN / ACTIONS_CACHE_URL during vcpkg install. I fixed it in commit 3c8ff72 by setting VCPKG_BINARY_SOURCES: clear at job level in .github/workflows/build-and-test.yml, which disables the GHA binary source and lets configure proceed.

[Alberto-o]

MIssing: test counting elements and checking there are more quads than w/o volume filling, and there no triangles, i.e., the volume is correctly filled