fix(dev): handle empty pyrefly target paths

Build the pyrefly command before execution and append target paths only when provided so Bash 3.2 with nounset does not fail on an empty array.

dev/pyrefly-check-local

@@ -34,8 +34,16 @@ if [[ -f "$EXCLUDES_FILE" ]]; then
 fi
 
 tmp_output="$(mktemp)"
+pyrefly_command=(
+  uv run --directory api --dev pyrefly check
+  "${pyrefly_args[@]}"
+)
+if (( ${#target_paths[@]} > 0 )); then
+  pyrefly_command+=("${target_paths[@]}")
+fi
+
 set +e
-uv run --directory api --dev pyrefly check "${pyrefly_args[@]}" "${target_paths[@]}" >"$tmp_output" 2>&1
+"${pyrefly_command[@]}" >"$tmp_output" 2>&1
 pyrefly_status=$?
 set -e