web: sync-guard gradient repair, FineWeb-Edu hardcoded (parquet /data streaming), dispatch-optimized backward (bit-identical), IEEE-754 oracle + corpus mutation tests, TEST_RESULTS.md

Release: SpikeWhale slider panel (HF dataset picker, stop/back), DaisyChain-Web (P2P WebRTC training, DaisyAdam, checkpoints, room host approval, verified-units-only)