feat(viz): tree/BFS/DFS patterns

frontend/src/lib/visualizations/types.ts

@@ -82,6 +82,10 @@ export interface DataState {
   linkedListPointers?: LinkedListPointerState[];
   // Stack support
   stacks?: StackState[];
+  // Tree support
+  trees?: BinaryTreeState[];
+  // Queue support
+  queues?: QueueState[];
 }
 
 /** Single step in the visualization */
@@ -203,3 +207,42 @@ export interface StackState {
   elements: StackElementState[];
   label?: string;
 }
+
+// ============================================
+// Binary Tree Types
+// ============================================
+
+/** State of a binary tree node */
+export interface BinaryTreeNodeState {
+  id: string;
+  value: number;
+  state: 'normal' | 'current' | 'visiting' | 'visited' | 'highlighted';
+  left: string | null;
+  right: string | null;
+}
+
+/** Complete binary tree state */
+export interface BinaryTreeState {
+  id: string;
+  nodes: BinaryTreeNodeState[];
+  rootId: string;
+  label?: string;
+}
+
+// ============================================
+// Queue Types
+// ============================================
+
+/** State of a queue element */
+export interface QueueElementState {
+  id: string;
+  value: number | string;
+  state: 'normal' | 'highlighted' | 'enqueued' | 'dequeued';
+}
+
+/** Complete queue state */
+export interface QueueState {
+  id: string;
+  elements: QueueElementState[];
+  label?: string;
+}