Simulate Plant Infection Spread

Given an `m x n` grid representing farmland: - `0` = empty cell - `1` = healthy plant - `2` = infected plant - `3` = obstacle Every minute, each infected plant spreads infection to its 4-directional neighboring healthy plants. Infection cannot pass through obstacles. Implement a function that returns the minimum number of minutes required to infect all reachable healthy plants. Return `-1` if at least one healthy plant can never be infected. Possible follow-ups: 1. Return the infection time for every plant. 2. Support multiple initially infected cells. 3. Explain the time and space complexity. 4. Modify the simulation if diagonal spread is allowed. 5. Discuss how you would process very large grids efficiently.