build: update `blsful` to resolve `rand` soundness advisory RUSTSEC-2026-0097

[xdustinface]

Background

RUSTSEC-2026-0097 was published on 2026-04-11 and flags rand >= 0.7.0, < 0.9.3 (and 0.10.0) as unsound. The patched versions are >= 0.9.3 or >= 0.10.1.

Our dependency chain: dashcore (feature bls) → blsful v3.0.0 (pinned git rev 0c34a7a4) → rand 0.8.5.

Current workaround

RUSTSEC-2026-0097 is currently ignored in deny.toml because upgrading requires blsful to update its rand dependency first.

Task

1. Check whether agora-blsful has a commit/tag that depends on rand >= 0.9.3 or >= 0.10.1.
2. Update the blsful git rev (or version) in dash/Cargo.toml accordingly.
3. Verify the BLS feature still compiles and tests pass: cargo test -p dashcore --features bls.
4. Remove the RUSTSEC-2026-0097 ignore entry from deny.toml.

References

• Advisory: https://rustsec.org/advisories/RUSTSEC-2026-0097.html
• Upstream rand fix: Prepare v0.10.1: deprecate feature log rust-random/rand#1763