feat: add project save/load with .wheel files and auto-save thread

Co-authored-by: aider (deepseek/deepseek-coder) <aider@aider.chat>

dispatcher.h

@@ -121,6 +121,8 @@ typedef enum {
     ACTION_RACK_SET_PARAMETER,
     ACTION_RACK_SET_VOLUME,
     ACTION_RACK_BYPASS,
+    ACTION_SAVE_PROJECT,
+    ACTION_LOAD_PROJECT,
     ACTION_PROCESS_AUDIO,
     ACTION_QUIT
 } ActionType;
@@ -144,6 +146,8 @@ typedef struct {
         struct { int channel; int plugin_index; int param_index; float value; } rack_set_parameter;
         struct { int channel; float volume; } rack_set_volume;
         struct { int channel; bool bypass; } rack_bypass;
+        struct { char filename[512]; } save_project;
+        struct { char filename[512]; } load_project;
         struct { jack_nframes_t nframes; } process_audio;
     } data;
 } Action;