Disassembled the SV1.3 app image and confirmed the shift-register
(HSPI 13/14 + latch 15), WS2812 (12), LDR (A0) and button pins, the
16-bit bit map and the tube order. The stock firmware has no I2C code
and drives a DFPlayer on UART0. Adds the ELF/xref helper tools.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
