Document the HT32F491x3 ESK32 board, build steps,
flashing flow, and validation commands. Add WSL and
PowerShell flash backends plus a Python wrapper.
Signed-off-by: Felipe Moura <moura.fmo@gmail.com>
Add initial HT32F491x3 support with startup, IRQ handling,
serial console, GPIO helpers, custom vectors, and CMake build files.
Signed-off-by: Felipe Moura <moura.fmo@gmail.com>