Salience docs / Setup and fixes

Stylize: Mac requirements

Stylize needs 16 to 64 GB of unified memory depending on the model. Salience checks whether this specific Mac is ready rather than quoting one hard-coded number, the Mac counterpart to the Windows GPU check.

If the check doesn't pass, Generate, Edit, and your installed Styles are unaffected; only creating new Styles is limited. Once your Mac clears it, head to Stylize to teach Salience a new sound character.