YT-CPPGL-68: Implement missing vertex view getters

- Extended the graph class with missing vertex collection getters:
  - Descriptor getters: neighbors, predecessors, successors
  - ID getters: neighbor_ids, predecessor_ids, successor_ids
- Fixed the incident_edges logic error:
  - Previously the function always called out_edges, which is correct for undirected graphs but not for directed graphs
  - Extended the internal implementation classes with specific incident edges getters
  - Aligned the graph class methods to use the proper underlying implementation type's methods
- Changed the are_incident method names for vertex pairs and edge pairs to use the proper term (are_adjacent)
- Cleaned up the layout of methods in the graph class and the implementation classes
- Cleaned up the gl module tests

Author: SpectraL519

benchmarks/suites/is_bipartite.cpp

@@ -3,7 +3,7 @@
 
 #include <gl/algorithm.hpp>
 #include <gl/graph.hpp>
-#include <gl/topologies.hpp>
+#include <gl/topology.hpp>
 
 #include <benchmark/benchmark.h>
 

include/gl/algorithm/spanning_tree/prim_mst.hpp

@@ -51,7 +51,7 @@ template <traits::c_undirected_graph G>
     if (root_id == invalid_id)
         root_id = initial_id;
 
-    for (const auto& edge : graph.incident_edges(root_id))
+    for (const auto& edge : graph.out_edges(root_id))
         edge_queue.emplace(edge);
 
     // mark the root vertex as visited

include/gl/algorithm/templates/bfs.hpp

@@ -55,7 +55,7 @@ bool bfs(
             if (not visit(node.vertex_id, node.pred_id))
                 return false;
 
-        for (const auto& edge : graph.incident_edges(node.vertex_id)) {
+        for (const auto& edge : graph.out_edges(node.vertex_id)) {
             const auto target_vertex_id = edge.other(node.vertex_id);
             const auto enqueue = enqueue_vertex_pred(target_vertex_id, edge);
             if (enqueue == decision::abort)

include/gl/algorithm/templates/dfs.hpp

@@ -55,7 +55,7 @@ bool dfs(
             if (not visit(node.vertex_id, node.pred_id))
                 return false;
 
-        for (const auto& edge : graph.incident_edges(node.vertex_id)) {
+        for (const auto& edge : graph.out_edges(node.vertex_id)) {
             const auto target_vertex_id = edge.other(node.vertex_id);
             if (enqueue_vertex_pred(target_vertex_id, edge))
                 s.emplace(target_vertex_id, node.vertex_id);
@@ -96,7 +96,7 @@ void r_dfs(
     visit(vertex_id, pred_id);
 
     // recursively search vertices adjacent to the current vertex
-    for (const auto& edge : graph.incident_edges(vertex_id)) {
+    for (const auto& edge : graph.out_edges(vertex_id)) {
         const auto target_vertex_id = edge.other(vertex_id);
         if (enqueue_vertex_pred(target_vertex_id, edge))
             r_dfs(

include/gl/algorithm/templates/pfs.hpp

@@ -59,7 +59,7 @@ bool pfs(
             if (not visit(node.vertex_id, node.pred_id))
                 return false;
 
-        for (const auto& edge : graph.incident_edges(node.vertex_id)) {
+        for (const auto& edge : graph.out_edges(node.vertex_id)) {
             const auto target_vertex_id = edge.other(node.vertex_id);
             const auto enqueue = enqueue_vertex_pred(target_vertex_id, edge);
             if (enqueue == decision::abort)