The selected game root could supply an unbounded legacy library index whose
revision was copied verbatim into app-owned state. A revision of `u64::MAX`
made every later checked revision advance fail even after the original root was
removed.
Read only a bounded regular, non-link file whose identity stays stable across
the read. Deserialize it before publication, preserve its cached game data, and
reset its stale revision authority to zero. Existing app-owned state still wins
without reading the legacy source, and invalid input remains in place for
recovery.
Test Plan:
- `just test` -- passed outside the sandbox; 494 peer tests and all workspace
targets passed.
- The initial sandboxed `just test` reached an unrelated Unix-socket permission
denial, then passed unchanged with the required socket permission.
- `git diff --cached --check` -- passed.
ddidderr
7de373afb6