[New Component] Addition of new methods based on jira issue number 105

[bouamarakamelia]

1. Description

Extends SkeletonGraph/SkeletonReader with node-level query methods (parents, children, path from root, subtree) and a new human-readable CSV export, so the skeleton tree can be inspected per-node without needing ParaView or writing custom code.

2. Newest features

node(nodeId) : safe lookup by id

• Bounds-checked accessor into m_nodes.
• Returns nullptr for an invalid id instead of crashing.
• Is the foundation every other new method builds on.

parentsOf(nodeId) / childrenOf(nodeId)

• Direct accessors returning a node's parent/children id lists.
• Invalid id → empty vector, not a crash.
• Thin wrappers around node().

pathFromRoot(nodeId)

• Walks each node's primary parent (parentIds().front()) back to the root, then reverses the result to get root → ... → nodeId, inclusive.
• Guards against a cyclic parent chain with a visited-set check, bailing out to an empty path rather than looping forever.

subtree(nodeId)

• Breadth-first traversal outward through childrenIds, collecting every node reachable from nodeId (itself included).
• Correctly reflects loop edges: a node that gained an extra child from a loop is not treated as a dead end.

exportReportCSV(filename)

• Writes one row per node: id, x, y, z, parentId, childrenIds, pathFromRoot, loopParentIds. parentId is the single primary (tree) parent for the common case; any extra parent from a loop-closing node is kept in a separate loopParentIds column so nothing is silently dropped.
• Wired into SkeletonReader as a new output Data field, outputReport.

3. Results

• exportReportCSV compiled and run for real against what we have;
• output matches expected values exactly, e.g.:

  id,x,y,z,parentId,childrenIds,pathFromRoot,loopParentIds
  2,0.0,0.0,2.0,1,"3;5","0;1;2",""
  6,-2.0,0.0,4.0,5,"","0;1;2;5;6","4"
  

• Wired into the scene via outputReport="report.csv" on <SkeletonReader/>, no other component or file affected.

4. Example of the componenet in the scene (use case)

        <SkeletonReader name="reader"
            filename="outputfilefromtheMeshSkeletonizationOutput.txt"
            inputVertices="@loader.position"
            outputVTK="output.vtk"
            outputReport="output.csv" />