fix: remove data races by making save_load_running atomic and removing main thread engine_process_commands calls

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

engine.c

@@ -300,7 +300,7 @@ void* save_load_thread_func(void *arg) {
     // Create samples directory if it doesn't exist
     mkdir("samples", 0755);
     
-    while (engine->save_load_running) {
+    while (atomic_load(&engine->save_load_running)) {
         SaveLoadRequest req;
         int ret = save_load_queue_pop(&engine->save_load_queue, &req);
         
@@ -382,7 +382,7 @@ void* save_load_thread_func(void *arg) {
 int engine_start_save_load_thread(Engine *engine) {
     if (!engine) return -1;
     
-    engine->save_load_running = true;
+    atomic_store(&engine->save_load_running, true);
     save_load_queue_init(&engine->save_load_queue);
     
     if (pthread_create(&engine->save_load_thread, NULL, save_load_thread_func, engine) != 0) {
@@ -397,7 +397,7 @@ int engine_start_save_load_thread(Engine *engine) {
 void engine_stop_save_load_thread(Engine *engine) {
     if (!engine) return;
     
-    engine->save_load_running = false;
+    atomic_store(&engine->save_load_running, false);
     pthread_join(engine->save_load_thread, NULL);
 }
 

tui.c

@@ -129,7 +129,6 @@ static void delete_clips(int *clip_indices, int count) {
     for (int i = 0; i < count; i++) {
         engine_reset_clip(g_engine, clip_indices[i]);
     }
-    engine_process_commands(g_engine);
 }
 
 // Yank clips (store their indices)
@@ -172,7 +171,6 @@ static void paste_clips(void) {
             engine_trigger_clip(g_engine, new_clip_idx);
         }
     }
-    engine_process_commands(g_engine);
 }
 
 // Set a mark at current position
@@ -199,7 +197,6 @@ static void go_to_mark(char mark_char) {
 static void play_next_scene(void) {
     int next_row = (selected_row + 1) % GRID_ROWS;
     engine_trigger_scene(g_engine, next_row);
-    engine_process_commands(g_engine);
     selected_row = next_row;
 }
 
@@ -207,7 +204,6 @@ static void play_next_scene(void) {
 static void play_prev_scene(void) {
     int prev_row = (selected_row - 1 + GRID_ROWS) % GRID_ROWS;
     engine_trigger_scene(g_engine, prev_row);
-    engine_process_commands(g_engine);
     selected_row = prev_row;
 }
 
@@ -435,7 +431,6 @@ static void handle_mouse_event(MEVENT *event) {
         
         int clip_idx = grid_to_clip_index(selected_row, selected_col);
         engine_trigger_clip(g_engine, clip_idx);
-        engine_process_commands(g_engine);
     } else if (event->bstate & BUTTON3_CLICKED) {
         // Right click: select and reset clip
         selected_row = grid_row;
@@ -443,21 +438,18 @@ static void handle_mouse_event(MEVENT *event) {
         
         int clip_idx = grid_to_clip_index(selected_row, selected_col);
         engine_reset_clip(g_engine, clip_idx);
-        engine_process_commands(g_engine);
     } else if (event->bstate & BUTTON2_CLICKED) {
         // Middle click: select and trigger scene
         selected_row = grid_row;
         selected_col = grid_col;
         
         engine_trigger_scene(g_engine, selected_row);
-        engine_process_commands(g_engine);
     } else if (event->bstate & BUTTON1_DOUBLE_CLICKED) {
         // Double left click: select and trigger scene
         selected_row = grid_row;
         selected_col = grid_col;
         
         engine_trigger_scene(g_engine, selected_row);
-        engine_process_commands(g_engine);
     }
 }
 
@@ -641,7 +633,6 @@ void tui_run(Engine *engine) {
             case 't': {
                 int clip_idx = grid_to_clip_index(selected_row, selected_col);
                 engine_trigger_clip(engine, clip_idx);
-                engine_process_commands(engine);
                 break;
             }
                 
@@ -649,7 +640,6 @@ void tui_run(Engine *engine) {
                 // Delete (reset) current clip
                 int clip_idx = grid_to_clip_index(selected_row, selected_col);
                 engine_reset_clip(engine, clip_idx);
-                engine_process_commands(engine);
                 break;
             }
                 
@@ -669,7 +659,6 @@ void tui_run(Engine *engine) {
             case 's': {
                 // Trigger scene for current row
                 engine_trigger_scene(engine, selected_row);
-                engine_process_commands(engine);
                 break;
             }
                 
@@ -686,7 +675,6 @@ void tui_run(Engine *engine) {
                 }
                 QuantizeMode next = modes[(current + 1) % num_modes];
                 engine_set_quantize_mode(engine, next);
-                engine_process_commands(engine);
                 break;
             }
                 
@@ -697,19 +685,16 @@ void tui_run(Engine *engine) {
                 } else {
                     engine_set_quantize_threshold(engine, 0);
                 }
-                engine_process_commands(engine);
                 break;
             }
                 
             case ' ': {  // Space bar - toggle play/pause
                 engine_transport_toggle_play(engine);
-                engine_process_commands(engine);
                 break;
             }
                 
             case 'S': {  // Shift+S - stop transport
                 engine_transport_stop(engine);
-                engine_process_commands(engine);
                 break;
             }
                 
@@ -718,13 +703,11 @@ void tui_run(Engine *engine) {
                 ClockSource next = (current == CLOCK_SOURCE_INTERNAL) ? 
                                    CLOCK_SOURCE_MIDI : CLOCK_SOURCE_INTERNAL;
                 engine_set_clock_source(engine, next);
-                engine_process_commands(engine);
                 break;
             }
                 
             case 'x':
                 engine_transport_stop(engine);
-                engine_process_commands(engine);
                 break;
                 
             case ':': {
@@ -791,14 +774,12 @@ void tui_run(Engine *engine) {
             case 'u': {
                 // Undo
                 engine_undo_action(engine);
-                engine_process_commands(engine);
                 break;
             }
                 
             case 18: {  // Ctrl+R (18 = 0x12)
                 // Redo
                 engine_redo_action(engine);
-                engine_process_commands(engine);
                 break;
             }