added usb - can bridge (loopback)

prj.conf

@@ -0,0 +1,43 @@
+# c version
+CONFIG_MAIN_STACK_SIZE=32768
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=8192
+CONFIG_ISR_STACK_SIZE=2048
+CONFIG_USBD_THREAD_STACK_SIZE=4096
+CONFIG_CPP=y
+CONFIG_NEWLIB_LIBC=y
+CONFIG_NEWLIB_LIBC_NANO=n
+CONFIG_PICOLIBC=n
+CONFIG_MINIMAL_LIBC=n
+CONFIG_POSIX_API=y
+
+#threads
+CONFIG_INIT_STACKS=y
+CONFIG_THREAD_STACK_INFO=y
+CONFIG_DEBUG=y
+CONFIG_DEBUG_THREAD_INFO=y
+
+CONFIG_CONSOLE=y
+
+# logging
+CONFIG_LOG=y
+CONFIG_LOG_MODE_IMMEDIATE=y
+CONFIG_STDOUT_CONSOLE=y
+CONFIG_PRINTK=y
+CONFIG_LOG_DEFAULT_LEVEL=3
+
+# Enable CDC ACM (virtual COM port)
+CONFIG_SERIAL=y
+CONFIG_UART_LINE_CTRL=y
+CONFIG_USBD_CDC_ACM_CLASS=y
+CONFIG_USB_DEVICE_STACK_NEXT=y
+CONFIG_USBD_CDC_ACM_WORKQUEUE=y
+CONFIG_UDC_WORKQUEUE=y
+CONFIG_UDC_STM32=y
+CONFIG_UDC_STM32_STACK_SIZE=2048
+CONFIG_UDC_WORKQUEUE_STACK_SIZE=2048
+
+# can FD
+CONFIG_CAN=y
+CONFIG_CAN_FD_MODE=y
+CONFIG_CAN_STM32_FDCAN=y
+