[aguirreSL]

Adds pytta.generate.stochastic_ir(reverbTime, volume, distance=1, c=343, samplingRate=None, timeLength=None, seed=None), a synthetic impulse response of a diffuse room after the statistical model of Kuttruff, Room Acoustics, 6th ed. (2016), sec. 4.2. It covers ita_stochastic_room_impulse_response of the ITA-Toolbox without an HRTF:

1. The direct sound, 1 / distance, arrives at distance / c.
2. The reflections arrive as a Poisson process of density 4πc³t² / V (eq. 4.6), drawn with the inverse of its integral.
3. Each reflection has a random sign and the amplitude 10^(-3t / T) / (ct), so that the energy decays by 60 dB in the reverberation time T (eq. 4.7).

The ITA function belongs to an application of the ITA-Toolbox whose license is "all rights reserved", so nothing was taken from its code; this implementation is written from Kuttruff. One reverberation time applies to all frequencies, and a binaural response would need the HRTF convolution of each reflection, which is left out.

The tests in tests/test_stochastic_ir.py, for T = 0.8 s, V = 200 m³ and 3 m, print the measured values:

1. Nothing arrives before the direct sound, which has the amplitude 1 / distance.
2. Between 20 and 40 ms there are 49 reflections for 47 expected from eq. 4.6, within 4 standard deviations of the Poisson count.
3. The backward integrated energy gives T30 = 0.806 s, within 2 % of T.

Checked with Python 3.12, numpy 1.26 and scipy 1.17. The 7 failures of development (3 in test_h5io.py, 4 in test_pyttasave.py) are the same with and without this change.

Co-Authored-By: Claude Fable 5.1 noreply@anthropic.com