fix: write ring buffer data before second trigger in test_full_cycle

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

test_engine.c

@@ -179,6 +179,13 @@ void test_full_cycle(void) {
     
     // Recording -> Looping
     state->clips[0].write_position = 200;
+    
+    // Write data into the ring buffer so the reducer can copy it
+    for (size_t i = 0; i < 200; i++) {
+        state->record_buffer[0][i] = (float)i;
+    }
+    atomic_store(&state->record_write_pos[0], 200);
+    
     reducer(state, action);
     assert(state->clips[0].state == CLIP_LOOPING);
     assert(state->clips[0].buffer_size == 200);