R1350 YA105 minimal LED A/B test

Known-good base: upstream ath10k + Xiaomi YA105 board data + per-unit ART pre-cal.
ONLY functional change: LED GPIO mapping copied from the AC2350 mapping validated by the same physical R1350:
  GPIO5  System blue
  GPIO7  System yellow
  GPIO8  Internet blue
  GPIO15 Internet yellow
No custom pinmux. No WAN LED daemon. No wireless-default changes.

Persistent sysupgrade remains experimental. Use sysupgrade -n only after verifying SHA256 and preserving the known-good YA105 v3 recovery image.
Expected first test: boot, cold boot, reboot; System yellow during boot and blue when running.
