chore: import upstream snapshot with attribution

components/esp_stdio/include/esp_stdio.h

@@ -0,0 +1,50 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#pragma once
+
+#include "esp_err.h"
+#include "esp_stdio_cli_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define ESP_VFS_DEV_CONSOLE "/dev/console"
+
+/**
+ * @brief add uart/usb_serial_jtag/usb_otg_acmcdc virtual filesystem driver
+ *
+ * This function is called from startup code to enable serial output
+ */
+esp_err_t esp_stdio_register(void);
+
+/**
+ * @brief Install and enable the default stdio driver.
+ *
+ * Initializes the selected console backend and registers it as the active
+ * input and output stream source. After calling this function, standard I/O
+ * functions such as `printf` and terminal input will use the configured backend.
+ *
+ * Line endings are automatically configured for typical terminal use:
+ * - RX: CR (terminals send CR when Enter is pressed)
+ * - TX: CRLF (move cursor to beginning of next line on newline)
+ *
+ * @return ESP_OK if the driver is successfully installed, or an appropriate error code otherwise.
+ */
+esp_err_t esp_stdio_install_io_driver(void);
+
+/**
+ * @brief Uninstall the active stdio driver.
+ *
+ * Restores driver state and detaches the console backend from the standard I/O
+ * streams. Call this when shutting down or when replacing the current console
+ * driver with a different one.
+ */
+void esp_stdio_uninstall_io_driver(void);
+
+#ifdef __cplusplus
+}
+#endif