Replace grep-based restore with SHA1 matching via database.json.
The old grep heuristic failed for assets with renamed basenames
(dsi_nand_batocera42.bin) or special characters (MAME dots vs
spaces), and only restored to the first .gitignore match when
multiple paths shared a basename.
Fix 3 broken data directory sources:
- opentyrian: buildbot URL 404, use release asset
- syobonaction: invalid git_subtree URL, use GitHub archive
- stonesoup: same fix, adds 532 game data files
build.yml now downloads large-files release assets and copies them
to their bios/ paths (matched via .gitignore) before regenerating
the database. This fixes Batocera showing 675/680 instead of 679/680
on the remote (PS3UPDAT.PUP, dsi_nand.bin, PSVUPDAT.PUP were missing).
Local: Batocera 679/680, all others 100%.