chore(deps): bump ctutils to 0.4.4 for RUSTSEC-2026-0385 (#4638)

Fixes RUSTSEC-2026-0385: `ctutils` < 0.4.4 generates masks with branches
on secret values (`u128` mask generation / comparisons are not
constant-time on some targets).

- Advisory: https://rustsec.org/advisories/RUSTSEC-2026-0385
- Affected: `ctutils 0.4.2` pinned in `Cargo.lock`, reached transitively
via `digest 0.11` (RustCrypto)
- Change: `cargo update -p ctutils --precise 0.4.4`; single
lockfile-only change (patch bump, no API impact)

The `deny` CI job started failing for every PR head after the advisory
was published at 06:45Z today; `main`'s last `deny` run (05:51Z)
predates it and does not yet cover this advisory.

Cargo.lock

@@ -2230,9 +2230,9 @@ dependencies = [
 
 [[package]]
 name = "ctutils"
-version = "0.4.2"
+version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7d5515a3834141de9eafb9717ad39eea8247b5674e6066c404e8c4b365d2a29e"
+checksum = "12218662ccac37d9714f2191252553d67585b97df8c839cbe49e0bde278dc865"
 dependencies = [
  "cmov",
 ]