fold lives only on git.trevon.dev, but every SARIF report advertised
https://github.com/trvon/fold as the tool's information URI, so code
scanning UIs and SARIF viewers linked readers to a repository fold no
longer uses. The driver now points at https://git.trevon.dev/trevon/fold.
test_scan_e2e asserts the URI; it failed before this change.
Unit + integration coverage for the session's work: incremental project
graph/index, pcode encoder, unreachable/dead-branch, equiv/cross-TU,
div-by-zero/sign-conversion/int-truncation, use-after-free, quality-precision,
scan-router profile, source TU runner, detector plan, and the eval fixtures.
