新的架构设计文档和核心系统数据结构及接口声明

docs/min_core_draft/wm_backend.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "wm_event.h"
+#include "wm_plan.h"
+
+typedef struct wm_backend_t wm_backend_t;
+
+typedef struct wm_backend_api_t {
+  bool (*init)(wm_backend_t *backend);
+  bool (*next_event)(wm_backend_t *backend, wm_event_t *out);
+  bool (*apply_effect)(wm_backend_t *backend, const wm_effect_t *effect);
+  void (*flush)(wm_backend_t *backend);
+  void (*shutdown)(wm_backend_t *backend);
+} wm_backend_api_t;
+
+struct wm_backend_t {
+  const wm_backend_api_t *api;
+  void *impl;
+};