feat(core): 添加 command 定义及 command_buffer 维护功能

src/core/command_buffer.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <stddef.h>
+
+#include "core/command.h"
+
+typedef struct command_buffer_t {
+  command_t *items;
+  size_t count;
+  size_t capacity;
+} command_buffer_t;
+
+void command_buffer_reset(command_buffer_t *buffer);
+void command_buffer_cleanup(command_buffer_t *buffer);
+void command_buffer_push(command_buffer_t *buffer, const command_t *command);