Simulate 50 Neurons

Simulate N=50 neurons with random input and compute mean ± std of firing rates.

Your task:
1. Outer loop: for neuron in range(50), use np.random.seed(neuron)
2. Inner loop: run full simulation with random current
3. Count spikes per neuron (n_spikes counter, reset each outer loop)
4. Append spike count to spike_counts after inner loop
5. Compute: firing_rates = [count / t_max for count in spike_counts]
6. Print mean and std
7. Plot a histogram of firing_rates