Initial commit

components/usb_api/include/usb_api.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <stdbool.h>
+
+typedef void (*usb_api_line_handler_t)(const char *line);
+
+// Initialize USB Serial/JTAG line reader; pass handler for complete lines.
+void usb_api_init(usb_api_line_handler_t handler);
+
+// Non-blocking poll; call from main loop/task.
+void usb_api_tick(void);
+
+// Send a line to host (no automatic newline added).
+void usb_api_send_line(const char *line);
+
+// Return true when host is connected over USB Serial/JTAG.
+bool usb_api_is_connected(void);