Add totp-gb

[dmang-dev]

Adds totp-gb to the homebrew database.

A TOTP (RFC 6238) two-factor authenticator for the original Game Boy — same protocol as Google Authenticator. Pure C, built with GBDK-2020, MIT-licensed. Includes prebuilt ROMs for both DMG/SGB (unified) and Game Boy Color (palette-enhanced), five screenshots, and a complete game.json.

Highlights:

• MBC3+TIMER+RAM+BATTERY cart layout — uses the MBC3 hardware RTC for accurate timekeeping across power cycles
• Persistent SRAM storage for up to 8 accounts
• Procedurally-generated Super Game Boy border + per-account SGB palette swaps when run on an SGB
• Game Boy Color palette enhancement on the .gbc build
• Verified end-to-end via a Lua script that reads the live code off the BG tile map and matches against a 720-window precomputed table — proves the full crypto + RTC + UI pipeline on real GB hardware
• Sibling totp-gba repo for the native GBA port

Two playable ROMs included: totp-gb.gb (default; runs on DMG/GBP/SGB/GBC/GBA) and totp-gbc.gbc (GBC-required, palette-enhanced).