Host initdump (rust/uisim --bin initdump) showed mipidsi emits only SLPOUT,
MADCTL=0x48, INVON, COLMOD, NORON, DISPON — MADCTL already matches CircuitPython,
but the ST7796 extension setup (unlock, 0xB6 480-lines, power, gamma) is missing,
and sending it AFTER mipidsi's DISPON blanked the live panel. Replay the full
known-good st7796_init via Display::dcs() ending in its own DISPON. Adds the
initdump tool (capture init byte sequence on the host, no bench).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
508fae56fb