C481 reproducible evidence

Read the C481 report and checkpoint first. This packet preserves the latest File_52c input and the selected source files; it does not replace the older C480 evidence archive.

From this directory run:

python3 evidence/check.py --out replay.json

The output should match evidence/RESULTS.json. The runner uses Python standard libraries only and exact Fraction arithmetic. MANIFEST.sha256 covers every payload other than itself. The predecessor link is to the retrieved C480 checkpoint text snapshot.