fix: initialize chorus mode before applying preset

[TrueNix]

Summary

Fix a startup crash in Chorus::Chorus() by initializing awesome_mode before calling setpreset().

setpreset() calls changepar(), which can reach setvolume(). setvolume() branches on awesome_mode; when the member is still uninitialized it may take the awesome_mode path and dereference ldelay/rdelay before they are allocated, causing a SIGSEGV during startup.

Evidence

Observed on Fedora/Nobara with rakarrack 0.6.2:

Signal: 11 (SEGV)
#0 Chorus::changepar(int, int)
#1 Chorus::setpreset(int, int)
#2 Chorus::Chorus(float*, float*)
#3 RKR::RKR()
#4 main

Test plan

• Built successfully after applying the patch.
• Verified the patched binary starts without creating a new coredump.
• Confirmed the previously crashing Fedora/Nobara startup path no longer crashes.

[TrueNix]

Hey @dtimms 👋

Just a friendly nudge — this PR fixes the segfault that occurs when a preset is applied before the chorus mode has been initialized (calling init_chorus() before preset application). The fix is minimal and the branch is clean with no CI failures.

Happy to address any feedback if you have concerns. Thanks for maintaining rakarrack!