feat(backends): add CachyLLaMA support

Add CachyLLaMA as a GGUF-compatible llama.cpp fork backend with CPU and Vulkan builds on Linux and Metal on Apple silicon. Expose it through model import, document persistent SSD cache options, and wire CI path filtering and dependency updates.

Assisted-by: Codex:gpt-5

scripts/build/cachyllama-darwin.sh

@@ -0,0 +1,82 @@
+#!/bin/bash
+
+set -ex
+
+IMAGE_NAME="${IMAGE_NAME:-localai/cachyllama-darwin}"
+
+pushd backend/cpp/cachyllama
+
+# Single build via ggml CPU_ALL_VARIANTS: one binary plus the per-microarch Apple/arm
+# dylibs (apple_m1/m2_m3/m4, armv8.x) that ggml selects at runtime. GGML_METAL stays ON
+# and --target ggml also builds ggml-metal (via add_dependencies), so the Metal GPU
+# backend is still produced as a loadable libggml-metal.dylib.
+make cachyllama-cpu-all && \
+make cachyllama-grpc && \
+make cachyllama-rpc-server
+
+popd
+
+mkdir -p build/darwin
+mkdir -p backend-images
+mkdir -p build/darwin/lib
+
+cp -rf backend/cpp/cachyllama/cachyllama-cpu-all build/darwin/
+cp -rf backend/cpp/cachyllama/cachyllama-grpc build/darwin/
+cp -rf backend/cpp/cachyllama/cachyllama-rpc-server build/darwin/
+
+# Distribute the shared ggml/llama libraries from the CPU_ALL_VARIANTS build. Unlike the
+# old fully-static fallback build, these have @rpath install names, so the otool loop below
+# (which only copies deps that exist on disk) will not pick them up. The split is by suffix:
+#  - ggml emits its loadable backends (per-microarch CPU variants, metal, blas) with a .so
+#    suffix EVEN ON DARWIN. These go in the package ROOT next to the binary, because darwin
+#    run.sh execs the binary directly (no bundled ld.so) so ggml's executable-directory
+#    scan looks there.
+#  - the core libraries (libggml-base/libggml/libllama/libllama-common/libmtmd) use the
+#    platform .dylib suffix and are NEEDED deps; they go in lib/, resolved at load time via
+#    the DYLD_LIBRARY_PATH=lib that run.sh exports. -a preserves the version symlinks.
+SHLIBS=backend/cpp/cachyllama/ggml-shared-libs
+cp -a $SHLIBS/*.so build/darwin/
+cp -a $SHLIBS/*.dylib build/darwin/lib/
+
+# Set default additional libs only for Darwin on M chips (arm64)
+if [[ "$(uname -s)" == "Darwin" && "$(uname -m)" == "arm64" ]]; then
+    ADDITIONAL_LIBS=${ADDITIONAL_LIBS:-$(ls /opt/homebrew/Cellar/protobuf/**/lib/libutf8_validity*.dylib 2>/dev/null)}
+else
+    ADDITIONAL_LIBS=${ADDITIONAL_LIBS:-""}
+fi
+
+for file in $ADDITIONAL_LIBS; do
+  cp -rfv $file build/darwin/lib
+done
+
+for file in build/darwin/*; do
+  LIBS="$(otool -L $file | awk 'NR > 1 { system("echo " $1) } ' | xargs echo)"
+  for lib in $LIBS; do
+    # only libraries ending in dylib
+    if [[ "$lib" == *.dylib ]]; then
+        if [ -e "$lib" ]; then
+            cp -rvf "$lib" build/darwin/lib
+        fi
+    fi
+  done
+done
+
+echo "--------------------------------"
+echo "ADDITIONAL_LIBS: $ADDITIONAL_LIBS"
+echo "--------------------------------"
+
+echo "Bundled libraries:"
+ls -la build/darwin/lib
+
+
+cp -rf backend/cpp/cachyllama/run.sh build/darwin/
+
+PLATFORMARCH="${PLATFORMARCH:-darwin/arm64}"
+
+./local-ai util create-oci-image \
+        build/darwin/. \
+        --output ./backend-images/cachyllama.tar \
+        --image-name $IMAGE_NAME \
+        --platform $PLATFORMARCH
+
+rm -rf build/darwin