fix: add libclang-rt-18-dev to CI image for fuzz targets

The clang-18 runtime libraries (fuzzer, ubsan, asan) were missing
from the fastsync-ci:v8 image because libclang-rt-18-dev was not
installed. This caused all 6 fuzz targets to fail at link time with
'cannot find libclang_rt.fuzzer-x86_64.a'.

Added the package to Dockerfile, rebuilt and pushed v8.

Dockerfile

@@ -2,7 +2,7 @@ FROM ubuntu:24.04
 RUN apt-get update && apt-get install -y --no-install-recommends \
     gcc g++ make libc6-dev cmake libzstd-dev libssl-dev git ca-certificates curl cppcheck clang-format \
     python3 python3-pip python3-venv openssl openssh-client \
-    lcov valgrind clang && \
+    lcov valgrind clang libclang-rt-18-dev && \
     pip3 install --break-system-packages pytest && \
     curl -fsSL https://deb.nodesource.com/setup_20.x | bash - && \
     apt-get install -y --no-install-recommends nodejs && \