CLI: add nodes canvas snapshot + duration parsing

src/cli/parse-duration.ts

@@ -0,0 +1,27 @@
+export type DurationMsParseOptions = {
+  defaultUnit?: "ms" | "s" | "m";
+};
+
+export function parseDurationMs(
+  raw: string,
+  opts?: DurationMsParseOptions,
+): number {
+  const trimmed = String(raw ?? "")
+    .trim()
+    .toLowerCase();
+  if (!trimmed) throw new Error("invalid duration (empty)");
+
+  const m = /^(\d+(?:\.\d+)?)(ms|s|m)?$/.exec(trimmed);
+  if (!m) throw new Error(`invalid duration: ${raw}`);
+
+  const value = Number(m[1]);
+  if (!Number.isFinite(value) || value < 0) {
+    throw new Error(`invalid duration: ${raw}`);
+  }
+
+  const unit = (m[2] ?? opts?.defaultUnit ?? "ms") as "ms" | "s" | "m";
+  const multiplier = unit === "ms" ? 1 : unit === "s" ? 1000 : 60_000;
+  const ms = Math.round(value * multiplier);
+  if (!Number.isFinite(ms)) throw new Error(`invalid duration: ${raw}`);
+  return ms;
+}