libretro_scraper: EXTRA_ARCADE_FILES adds namcoc69/70/75, msx, qsound
to arcade system. segasp.zip added to dreamcast-arcade. ep128emu
includes injected for enterprise system.
new profiles: vba_m (GB/GBC/GBA with doc vs source notes),
beetle_gba (Mednafen GBA).
shared groups in _shared.yml: np2kai, keropi, quasi88, kronos, ep128emu
with source references for each subdirectory requirement.
libretro_scraper: CORE_SUBDIR_MAP applies subdirectory prefixes at
generation time (np2kai/, keropi/, dc/). EXTRA_SYSTEMS adds QUASI88.
SYSTEM_SHARED_GROUPS injects includes for kronos/np2kai/keropi.
new BIOS: CPS3 (23 ZIPs), Cannonball OutRun (40 ROMs), PCem PC BIOS
(73 files), VICE Commodore ROMs, Spectrum ZIPs, dc_bios.bin, X1 fonts.
new emulator profiles: redream, melonds_ds, lrps2 with doc vs source
notes. platforms/README.md documents shared groups architecture.
Identical _fetch_raw() implementation (URL fetch + cache + error handling)
was duplicated in 4 scrapers. Moved to BaseScraper.__init__ with url param.
Each scraper now passes url to super().__init__() and inherits _fetch_raw().
Eliminates ~48 lines of duplicated code.
DRY audit now clean: resolve logic in common.py, scraper CLI in base_scraper,
_fetch_raw in BaseScraper. Remaining duplications are justified (different
list_platforms semantics, context-specific hash computation).
