fix(whisperx): use unsafe-best-match index strategy to fix uv resolution failure

uv's default first-match strategy finds torch on PyPI before checking
the extra index, causing it to pick torch==2.8.0+cu128 instead of the
CPU variant. This makes whisperx's transitive torch dependency
unresolvable. Using unsafe-best-match lets uv consider all indexes.

Signed-off-by: eureka928 <meobius123@gmail.com>

backend/python/common/libbackend.sh

@@ -436,7 +436,7 @@ function installRequirements() {
             if [ "x${USE_PIP}" == "xtrue" ]; then
                 pip install ${EXTRA_PIP_INSTALL_FLAGS:-} --requirement "${reqFile}"
             else
-                uv pip install ${EXTRA_PIP_INSTALL_FLAGS:-} --requirement "${reqFile}"
+                uv pip install --index-strategy unsafe-best-match ${EXTRA_PIP_INSTALL_FLAGS:-} --requirement "${reqFile}"
             fi
             echo "finished requirements install for ${reqFile}"
         fi