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.
Yes, when you create a custom board, we use a generic interrupt vector table so, for now, you have to create it, either manually or by looking in a similar evaluation board and copying the startup.s file.