Add Iterative Deepening DFS (IDDFS)

[R-Anurag]

Add Iterative Deepening DFS, which repeatedly applies DFS with increasing depth limits until the target is found.

Tasks:

• Implement IDDFS algorithm.
• Show animations for each depth level expansion.
• Display current depth level during visualization.

Acceptance Criteria:

• IDDFS explores progressively deeper layers.
• Visualization resets at each iteration and stops when the goal is found.