refactor(TopologicalSortAnalyzer): cache directed adjacency map and analysis result

TopologicalSortAnalyzer rebuilt the directed adjacency map (O(V+E)) in
every public method call — analyze(), analyzeDependencies(), countChoicePoints().
generateSummary() was worst: it called analyze() + countChoicePoints(), which
itself called analyze() again, resulting in 3× redundant O(V+E) traversals
and 3× redundant adjacency map constructions per summary generation.

Cache both buildDirectedAdj() and analyze() results as lazy instance fields.
Subsequent calls to any method reuse the cached structures instead of
recomputing from scratch.

Impact: generateSummary() drops from ~3× O(V+E) graph traversals to 1×.
analyzeDependencies() no longer rebuilds adjacency + re-runs full Kahn's
algorithm just to get the depth map.

Author: sauravbhattacharya001

Gvisual/src/gvisual/TopologicalSortAnalyzer.java

@@ -33,6 +33,12 @@ public class TopologicalSortAnalyzer {
 
     private final Graph<String, Edge> graph;
 
+    /** Lazily-computed directed adjacency — avoids rebuilding O(V+E) per method call. */
+    private GraphUtils.DirectedAdj cachedAdj;
+
+    /** Lazily-computed full analysis result — reused by generateSummary, countChoicePoints, analyzeDependencies. */
+    private TopologicalSortResult cachedResult;
+
     /**
      * Create a new analyzer for the given graph.
      *
@@ -188,7 +194,10 @@ public VertexDependencyInfo(String vertex, Set<String> allDependencies,
      * adjacency builder extracted from this class.
      */
     private GraphUtils.DirectedAdj buildDirectedAdj() {
-        return GraphUtils.buildDirectedAdjacencyMap(graph);
+        if (cachedAdj == null) {
+            cachedAdj = GraphUtils.buildDirectedAdjacencyMap(graph);
+        }
+        return cachedAdj;
     }
 
     // ── Core algorithms ─────────────────────────────────────────
@@ -206,6 +215,9 @@ private GraphUtils.DirectedAdj buildDirectedAdj() {
      * @return complete topological sort analysis
      */
     public TopologicalSortResult analyze() {
+        if (cachedResult != null) {
+            return cachedResult;
+        }
         GraphUtils.DirectedAdj adj = buildDirectedAdj();
         Map<String, Set<String>> successors = adj.successors;
         Map<String, Set<String>> predecessors = adj.predecessors;
@@ -301,9 +313,10 @@ public TopologicalSortResult analyze() {
             criticalPath = reconstructCriticalPath(depthMap, predecessors, longestPathLength);
         }
 
-        return new TopologicalSortResult(isDAG, sortedOrder, cycles, depthMap,
+        cachedResult = new TopologicalSortResult(isDAG, sortedOrder, cycles, depthMap,
                 dependencyCount, dependentCount, roots, leaves,
                 longestPathLength, criticalPath);
+        return cachedResult;
     }
 
     /**