Merge origin/master into feat/darwin-vllm-metal

Resolve includeDarwin conflict in backend-matrix.yml: keep both the vllm and
the newly-merged liquid-audio darwin entries (additive).

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:opus-4.8 [Claude Code]

backend/python/liquid-audio/install.sh

@@ -14,5 +14,11 @@ else
 fi
 
 # liquid-audio's torch wheels are large; allow upgrades to satisfy transitive pins
-EXTRA_PIP_INSTALL_FLAGS+=" --upgrade --index-strategy=unsafe-first-match"
+EXTRA_PIP_INSTALL_FLAGS+=" --upgrade"
+# --index-strategy is a uv-only flag. The darwin/MPS build installs with pip
+# (USE_PIP=true in scripts/build/python-darwin.sh), which rejects it. Only add
+# it on the uv path; Linux/CUDA resolution is unchanged.
+if [ "x${USE_PIP:-}" != "xtrue" ]; then
+    EXTRA_PIP_INSTALL_FLAGS+=" --index-strategy=unsafe-first-match"
+fi
 installRequirements

backend/python/liquid-audio/requirements-mps.txt

@@ -1,3 +1,4 @@
+# MPS (Apple Silicon / Metal) build profile - installed by the darwin CI job.
 torch>=2.8.0
 torchaudio>=2.8.0
 torchcodec>=0.9.1