feat(openthread): reorganize source file structure

components/openthread/private_include/esp_openthread_instance.h

@@ -0,0 +1,56 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include <stdbool.h>
+
+#include "openthread/instance.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Initialize OpenThread instance(s) for the selected build (single or multiple).
+ *
+ * @return true on success, false otherwise.
+ */
+bool esp_openthread_instances_init(void);
+
+/**
+ * @brief Finalize OpenThread instance(s) for the selected build (single or multiple).
+ *
+ * @param[in] instance  Instance provided by the caller (may be unused in multi-instance builds).
+ */
+void esp_openthread_instances_deinit(otInstance *instance);
+
+/**
+ * @brief Check whether tasklets are pending.
+ *
+ * @param[in] instance  Instance provided by the caller (may be unused in multi-instance builds).
+ */
+bool esp_openthread_tasklets_are_pending(otInstance *instance);
+
+/**
+ * @brief Process pending tasklets.
+ *
+ * @param[in] instance  Instance provided by the caller (may be unused in multi-instance builds).
+ */
+void esp_openthread_tasklets_process(otInstance *instance);
+
+/**
+ * @brief Initialize the NCP/RCP application for the selected instance mode.
+ *
+ * @param[in] instance  Instance provided by the caller (may be unused in multi-instance builds).
+ *
+ * @note Only used when CONFIG_OPENTHREAD_RADIO is enabled.
+ */
+void esp_openthread_ncp_app_init(otInstance *instance);
+
+#ifdef __cplusplus
+}
+#endif