Development tools for Zephyr on STM32Workbench for Zephyr: VS Code extension to set up, build, flash and debug Zephyr applications on STM32.Devicetree manager: browse, edit and visualize Zephyr devicetree, STM32CubeMX-like for Zephyr.
You also can see that the board is not present in the list when you create a project for the STM32F1 family.
Only Nucleo or Eval boards appear in the list.