fix: chmod +x overlay scripts on builder VM after git pull

macOS does not reliably apply git file mode changes on disk.
Run chmod explicitly on the VM where it matters.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/run-builder.sh

@@ -66,6 +66,7 @@ fi
 cd "\$REPO"
 echo "--- pulling latest ---"
 git pull --ff-only
+chmod +x iso/overlay-debug/etc/init.d/* iso/overlay-debug/usr/local/bin/*
 
 # Kill any previous build session
 screen -S bee-build -X quit 2>/dev/null || true