validation: Apply fixes for Bitcoin backport compliance

- Add BOOST_MULTI_INDEX_ENABLE_SAFE_MODE to native_fuzz CI config
- Add BOOST_MULTI_INDEX_ENABLE_SAFE_MODE to native_fuzz_with_valgrind CI config
- Add BOOST_MULTI_INDEX_ENABLE_SAFE_MODE to native_multiprocess CI config

These changes ensure that all CI jobs using --enable-debug or --enable-fuzz
explicitly enable boost multi index safe mode, matching Bitcoin's intent in
PR bitcoin#27724 which removed automatic enabling in configure.ac and re-enabled it
in specific CI jobs.

Author: Claude Code

ci/test/00_setup_env_native_fuzz.sh

@@ -9,7 +9,7 @@ export LC_ALL=C.UTF-8
 export CONTAINER_NAME=ci_native_fuzz
 export PACKAGES="clang llvm python3 libevent-dev bsdmainutils libboost-dev"
 export DEP_OPTS="NO_UPNP=1 DEBUG=1"
-export CPPFLAGS="-DDEBUG_LOCKORDER -DARENA_DEBUG"
+export CPPFLAGS="-DDEBUG_LOCKORDER -DARENA_DEBUG -DBOOST_MULTI_INDEX_ENABLE_SAFE_MODE"
 export PYZMQ=true
 export RUN_UNIT_TESTS=false
 export RUN_FUNCTIONAL_TESTS=false

ci/test/00_setup_env_native_fuzz_with_valgrind.sh

@@ -15,5 +15,5 @@ export RUN_FUZZ_TESTS=true
 export FUZZ_TESTS_CONFIG="--valgrind"
 export GOAL="install"
 # Temporarily pin dwarf 4, until valgrind can understand clang's dwarf 5
-export BITCOIN_CONFIG="--enable-fuzz --with-sanitizers=fuzzer CC=clang-18 CXX=clang++-18 CFLAGS='-gdwarf-4' CXXFLAGS='-gdwarf-4'"
+export BITCOIN_CONFIG="--enable-fuzz --with-sanitizers=fuzzer CC=clang-18 CXX=clang++-18 CFLAGS='-gdwarf-4' CPPFLAGS='-DBOOST_MULTI_INDEX_ENABLE_SAFE_MODE' CXXFLAGS='-gdwarf-4'"
 export CCACHE_SIZE=200M

ci/test/00_setup_env_native_multiprocess.sh

@@ -13,7 +13,7 @@ export DEP_OPTS="MULTIPROCESS=1 CC=clang-18 CXX=clang++-18"
 export RUN_TIDY=true
 export GOAL="install"
 export TEST_RUNNER_EXTRA="--v2transport"
-export BITCOIN_CONFIG="--with-boost-process --enable-debug CC=clang-18 CXX=clang++-18" # Use clang to avoid OOM
+export BITCOIN_CONFIG="--with-boost-process --enable-debug CC=clang-18 CXX=clang++-18 CPPFLAGS='-DBOOST_MULTI_INDEX_ENABLE_SAFE_MODE'" # Use clang to avoid OOM
 # Additional flags for RUN_TIDY
 export BITCOIN_CONFIG="${BITCOIN_CONFIG} --disable-hardening CFLAGS='-O0 -g0' CXXFLAGS='-O0 -g0 -Wno-error=documentation'"
 export BITCOIND=dash-node  # Used in functional tests