All playvoice calls use volume 128, but earlier chapters used 256

It was brought up on discord that the playvoice calls for Matsuribayashi have their volume set to 128, but all other previous chapters use 256.

We had some reports that the BGM/SE were too loud in this chapter, and this could be the cause.

However, I think nobody has A/B tested the actual volume (with the default settings) to confirm this, in case the volume was set lower deliberately (perhaps because this chapter handles voices differently)

We should also check whether Ch.9 has the same issue.

I was wondering whether the volume for ch.8 was capped at 128, but apparently we play the PS2 voices at a higher volume (540) to compensate for them being quieter, so this is probably not the case.

TODO:

- [ ] Check whether voices are quieter in Ch.8 than previous chapters
- [ ] Check whether Ch.9 has same issue
- [ ] Fix voice volumes to 256 (if necessary)

Find the playvoice calls in the codebase for chapters 8 and 9, likely in script files. Compare the volume parameter (128 vs 256). Test the audio levels in-game to confirm the issue. If confirmed, change the volume values to 256 and verify the fix doesn't break other audio handling.

Written by the indexing model from the issue text.