add firmware source code (#4)

* add firmware source code

firmware/main/stackchan/stackchan.h

@@ -0,0 +1,180 @@
+/*
+ * SPDX-FileCopyrightText: 2026 M5Stack Technology CO LTD
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#pragma once
+#include "modifiable.h"
+#include "modifiers/modifiers.h"
+#include "json/json_helper.h"
+#include <memory>
+
+namespace stackchan {
+
+/**
+ * @brief
+ *
+ */
+class StackChan : public Modifiable {
+public:
+    /**
+     * @brief Attach motion instance
+     *
+     * @param yawServo
+     * @param pitchServo
+     */
+    void attachMotion(std::unique_ptr<motion::Motion> motion)
+    {
+        _motion = std::move(motion);
+    }
+
+    /**
+     * @brief Reset and destroy attached motion instance
+     *
+     */
+    void resetMotion()
+    {
+        _motion.reset();
+    }
+
+    /**
+     * @brief Attach avatar instance
+     *
+     * @param avatar
+     */
+    void attachAvatar(std::unique_ptr<avatar::Avatar> avatar)
+    {
+        _avatar = std::move(avatar);
+    }
+
+    /**
+     * @brief Reset and destroy attached avatar instance
+     *
+     */
+    void resetAvatar()
+    {
+        _avatar.reset();
+    }
+
+    /**
+     * @brief Get motion instance
+     *
+     * @return motion::Motion&
+     */
+    motion::Motion& motion() override
+    {
+        return *_motion;
+    }
+
+    /**
+     * @brief Get avatar instance
+     *
+     * @return avatar::Avatar&
+     */
+    avatar::Avatar& avatar() override
+    {
+        return *_avatar;
+    }
+
+    /**
+     * @brief Check if avatar is attached
+     *
+     * @return true
+     * @return false
+     */
+    bool hasAvatar() override
+    {
+        if (_avatar) {
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * @brief Check if motion is attached
+     *
+     * @return true
+     * @return false
+     */
+    bool hasMotion()
+    {
+        if (_motion) {
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * @brief Add modifier
+     *
+     * @param modifier
+     * @return int
+     */
+    int addModifier(std::unique_ptr<Modifier> modifier)
+    {
+        return _modifier_pool.create(std::move(modifier));
+    }
+    Modifier* getModifier(int id)
+    {
+        return _modifier_pool.get(id);
+    }
+    bool removeModifier(int id)
+    {
+        return _modifier_pool.destroy(id);
+    }
+    void clearModifiers()
+    {
+        _modifier_pool.clear();
+    }
+
+    /**
+     * @brief Update
+     *
+     */
+    void update()
+    {
+        _modifier_pool.forEach([this](Modifier* modifier, int id) { modifier->_update(*this); });
+        _modifier_pool.cleanup();
+
+        if (_avatar) {
+            _avatar->update();
+        }
+
+        if (_motion) {
+            _motion->update();
+        }
+    }
+
+    /**
+     * @brief
+     *
+     * @param jsonContent
+     */
+    void updateAvatarFromJson(const char* jsonContent)
+    {
+        if (_avatar) {
+            avatar::update_from_json(_avatar.get(), jsonContent);
+        }
+    }
+
+    /**
+     * @brief
+     *
+     * @param jsonContent
+     */
+    void updateMotionFromJson(const char* jsonContent)
+    {
+        if (_motion) {
+            motion::update_from_json(_motion.get(), jsonContent);
+        }
+    }
+
+private:
+    std::unique_ptr<avatar::Avatar> _avatar;
+    std::unique_ptr<motion::Motion> _motion;
+    ObjectPool<Modifier> _modifier_pool;
+};
+
+}  // namespace stackchan
+
+stackchan::StackChan& GetStackChan();