fix: sanitizer sweep across all generators; bound signed shifts/division/overflow at coordinate limits (L61); R31

New verify.py sanitize tier (Clang address,undefined,float-cast-overflow; GCC address,undefined;
-fno-sanitize-recover) runs 19 cases per compiler at LOD0-8 across every generator, passages and the
crossing: 0 runtime reports; a planted signed-overflow control is caught by both. A static scan fixed
INT_MIN negation in floor division, unbounded signed LOD shifts and coordinate-times-extent overflow in
VoxelClipmapDesiredTiles.h and VoxelTypes.h (plugin and standalone), and VoxelWorld.cpp, VoxelContentManager.cpp
and VoxelDensityVolume.cpp (plugin only, uncompiled here). Supported-input output unchanged (version 211).
fast/medium/full PASS. Research R31 (self-checked): far-LOD 4-8 cut plan.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Standalone/BuildLinux.sh

@@ -13,6 +13,8 @@ COMPILER="clang++-19"
 VARIANT="clang19"
 FP_CONTRACT="off"
 JOBS=12
+SANITIZERS=""
+EXCLUDE_UNSIGNED_OVERFLOW=0
 
 while (($#)); do
     case "$1" in
@@ -20,6 +22,8 @@ while (($#)); do
         --variant=*) VARIANT="${1#*=}" ;;
         --fp-contract=*) FP_CONTRACT="${1#*=}" ;;
         --jobs=*) JOBS="${1#*=}" ;;
+        --sanitize=*) SANITIZERS="${1#*=}" ;;
+        --exclude-unsigned-integer-overflow) EXCLUDE_UNSIGNED_OVERFLOW=1 ;;
         *) printf 'Unknown build option: %s\n' "$1" >&2; exit 2 ;;
     esac
     shift
@@ -60,11 +64,22 @@ INCLUDES=(
     "-I$ROOT/Source/VoxelForge/Public"
     "-I$ROOT/Source/VoxelForge/Private"
 )
+OPT_LEVEL=-O2
+LINK_FLAGS=()
+if [[ -n "$SANITIZERS" ]]; then
+    OPT_LEVEL=-O1
+    LINK_FLAGS+=("-fsanitize=$SANITIZERS" -fno-sanitize-recover=undefined)
+    if ((EXCLUDE_UNSIGNED_OVERFLOW)); then
+        LINK_FLAGS+=(-fno-sanitize=unsigned-integer-overflow)
+    fi
+fi
+
 FLAGS=(
-    -std=c++20 -O2 -mavx2 -mfma -fno-fast-math
+    -std=c++20 "$OPT_LEVEL" -mavx2 -mfma -fno-fast-math
     -fexceptions -pthread "${INCLUDES[@]}"
     "-DVOXELFORGE_SOURCE_STAMP=\"$SOURCE_STAMP\""
 )
+FLAGS+=("${LINK_FLAGS[@]}")
 if [[ "$FP_CONTRACT" != "default" ]]; then
     FLAGS+=("-ffp-contract=$FP_CONTRACT")
 fi
@@ -131,7 +146,7 @@ PIDS=()
 CORE_LIBRARY="$BUILD_DIR/libVoxelForgeCore.a"
 "$(command -v ar)" rcs "$CORE_LIBRARY" "${CORE_OBJECTS[@]}"
 OUTPUT="$BIN_DIR/VoxelForgeCoreHeadless-$VARIANT"
-"$COMPILER" -pthread "${LEGACY_OBJECTS[@]}" "$CORE_LIBRARY" -o "$OUTPUT"
+"$COMPILER" -pthread "${LINK_FLAGS[@]}" "${LEGACY_OBJECTS[@]}" "$CORE_LIBRARY" -o "$OUTPUT"
 CAPTURE_OUTPUT="$BIN_DIR/VoxelForgeOffscreenCapture-$VARIANT"
 "$COMPILER" -std=c++20 -O2 -fno-fast-math -pthread \
     "-DVOXELFORGE_SOURCE_STAMP=\"$SOURCE_STAMP\"" -I"$ROOT/Source" \
@@ -145,4 +160,5 @@ if [[ "$POST_BUILD_STAMP" != "$SOURCE_STAMP" ]]; then
 fi
 printf 'Built Core library: %s\nBuilt headless benchmark: %s\n' "$CORE_LIBRARY" "$OUTPUT"
 printf 'Built EGL offscreen capture: %s\n' "$CAPTURE_OUTPUT"
-printf 'Compiler: %s | variant: %s | fp-contract: %s | jobs: %s\n' "$COMPILER" "$VARIANT" "$FP_CONTRACT" "$JOBS"
+printf 'Compiler: %s | variant: %s | fp-contract: %s | sanitizers: %s | jobs: %s\n' \
+    "$COMPILER" "$VARIANT" "$FP_CONTRACT" "${SANITIZERS:-off}" "$JOBS"