Given a directed acyclic graph represented as an adjacency list and a starting node, return a list of all nodes reachable from the starting node following the edges of the graph. **Function Signature:** `def reachable_nodes(graph: List[List[int]], start: int) -> List[int]:` **Constraints:** - The number of nodes will be between 1 and 10^4. - Each node is labeled with integers from 0 to n-1, where n is the number of nodes. **Example 1:** Input: `graph = [[1], [2], []], start = 0` Output: `[0, 1, 2]` **Example 2:** Input: `graph = [[2], [2], []], start = 1` Output: `[1, 2]`