refactor(numbers): share non-negative finite guard

src/shared/number-coercion.ts

@@ -1,2 +1,6 @@
 /** Shared numeric coercion facade for legacy imports inside core. */
 export * from "@openclaw/normalization-core/number-coercion";
+
+export function resolveNonNegativeNumber(value: number | null | undefined): number | undefined {
+  return typeof value === "number" && Number.isFinite(value) && value >= 0 ? value : undefined;
+}