build(deps): bump FreeUnit to 1.35.6-build5

Recompute the FREEUNIT_SHA256SUMS_SHA256 trust anchor against the new
release's SHA256SUMS. Base deb version 1.35.6-1 is unchanged; all matrixed
PHP lines (8.3/8.4/8.5) are present in the new checksum file.

Author: 6RUN0

Dockerfile

@@ -129,14 +129,14 @@ ARG DEBIAN_FRONTEND=noninteractive
 ARG SUITE
 ARG PHP_VER
 ARG FREEUNIT_VERSION=1.35.6-1
-ARG FREEUNIT_RELEASE=1.35.6-build4
+ARG FREEUNIT_RELEASE=1.35.6-build5
 # SHA256 of the release's SHA256SUMS file, pinned in version control as a trust
 # anchor. The .deb integrity check below verifies each package against
 # SHA256SUMS, but that file is fetched from the same release, so a release
 # compromise could replace both the .debs and their checksums. Pinning the
 # manifest digest here breaks that self-reference: tampering no longer passes,
 # because the expected value lives in this repo. Bump it with FREEUNIT_RELEASE.
-ARG FREEUNIT_SHA256SUMS_SHA256=3861b8f171042ce4f8bfd85ddbcf52cb28421fb1bfac3060df04d350ac5474b4
+ARG FREEUNIT_SHA256SUMS_SHA256=f1f5b74c6c0a64d5f3ec00ff0f1ecf55dc0786f20858ae9fb918370a359ab877
 ARG FREEUNIT_BASE_URL="https://github.com/6RUN0/freeunit/releases/download"
 # Brand identity, mirroring the upstream freeunit packaging vocabulary
 # (freeunit/pkg/deb/Makefile): BRAND is the dpkg/apt identity (asset/package