LB302: Lock oscilators

### Enhancement Summary

i know that the roland machine it tries to emulate has a free-running oscilator, HOWEVER: Sometimes, it would be nice to pair up multiple LB302s, but the phase cancelation isnt something i would like when they are running. so i request adding an ablity to switch between free-run and locked phase.

### Implementation Details / Mockup

add a on-off switch to the UI along the lines of "locked oscilator", and when enabled, lock the phase of the oscilator so it would reset on every note instead of free-run phase

### Please search the issue tracker for existing feature requests before submitting your own.

- [x] I have searched all existing issues and confirmed that this is not a duplicate.

Start by locating the LB302 oscillator implementation and its UI controls, then trace how note starts currently affect oscillator phase. Add the requested locked/free-running choice and verify that locked mode resets phase on each note while free-running mode remains unchanged.

Written by the indexing model from the issue text.