add --emulator, --system, --standalone, --list-emulators, --list-systems
to verify.py and generate_pack.py. packs are RTU with data directories,
regional BIOS variants, and archive support.
validation: field per file (size, crc32, md5, sha1) with conflict
detection. by_path_suffix index in database.json for regional variant
resolution via dest_hint. restructure GameCube IPL to regional subdirs.
66 E2E tests, full pipeline verified.
dsp_coef.bin, dsp_rom.bin, font_western.bin, font_japanese.bin copied
back to bios/Nintendo/GameCube/ (needed by verify.py, were moved to
data/ with the Sys folder). Pack includes 2537 files with Dolphin Sys.