fix(backends): derive darwin RUN_BINARY from the exec line only (#10541)

golang-darwin.sh's packaging check derived the launch binary by grepping every
$CURDIR/... reference in run.sh and taking the last one. Backends that pick a
runtime CPU variant assign it via unquoted `LIBRARY=$CURDIR/libgo<x>-avx512.so`
lines, so the heuristic returned `libgo<x>-avx512.so` — a variant Darwin never
builds (arm64 builds only fallback) — and the check then failed with
"package/libgo<x>-avx512.so not found ... refusing to package (#10267)",
breaking the darwin builds for whisper, sam3-cpp, vibevoice-cpp and friends.

Scan only the `exec` line(s) (the actual launch contract) and tolerate a
quoted `exec "$CURDIR"/<binary>`. parakeet-cpp's parakeet-cpp-grpc and the
quoted-only backends (sherpa/piper/opus) resolve correctly; no Linux change.

Assisted-by: Claude:claude-opus-4-8

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>

scripts/build/golang-darwin.sh

@@ -17,9 +17,15 @@ rm -rf "${BACKEND_DIR}"/build-*
 # run.sh's final `exec $CURDIR/<binary>` is the contract for what gets launched;
 # the binary is not always named after the backend (e.g. parakeet-cpp launches
 # parakeet-cpp-grpc), so derive it from run.sh and fall back to ${BACKEND}.
+#
+# Only scan the `exec` line(s): many run.sh select a runtime CPU variant via
+# unquoted `LIBRARY=$CURDIR/libgo<x>-avx512.so` lines, and a whole-file grep
+# would pick the last of those (avx512, which Darwin never builds) instead of
+# the binary — failing the check below for whisper/sam3-cpp/vibevoice-cpp/...
+# Also tolerate the exec being quoted (`exec "$CURDIR"/<binary>`).
 RUN_BINARY=""
 if [ -f "${BACKEND_DIR}/run.sh" ]; then
-        RUN_BINARY=$(grep -oE '\$CURDIR/[A-Za-z0-9._-]+' "${BACKEND_DIR}/run.sh" | grep -v 'ld\.so' | tail -1 | sed 's|\$CURDIR/||')
+        RUN_BINARY=$(grep -E '^[[:space:]]*exec[[:space:]]' "${BACKEND_DIR}/run.sh" | grep -oE '"?\$CURDIR"?/[A-Za-z0-9._-]+' | grep -v 'ld\.so' | tail -1 | sed -E 's|"?\$CURDIR"?/||')
 fi
 RUN_BINARY="${RUN_BINARY:-${BACKEND}}"