Update a Neuron Grid

You are given an `m x n` integer matrix `neurons`. - A cell is a **firing** neuron if its value is `0`. - A cell is a **non-firing** neuron if its value is greater than `0`. For each cell, count the number of firing neighbors among its 8 surrounding cells (horizontal, vertical, and diagonal). All updates must be applied **simultaneously** based on the original state of the matrix. Update the matrix using these rules: 1. If a cell is firing (`0`) and **exactly 3** of its neighbors are firing, its new value becomes `6`. 2. If a cell is non-firing and it has **0 or 1** firing neighbors, decrease its value by `2`. 3. If a cell is non-firing and it has **more than 3** firing neighbors, decrease its value by `1`. 4. A cell's value can never go below `0`. 5. In all other cases, the cell keeps its current value. Implement a function to update the matrix state. Follow-up: - First solve it using a copied matrix. - Then optimize the solution to use `O(1)` auxiliary space.