Rename .js to .mjs, extract helpers module

Move resolvePath and exec out of index.mjs into server/helpers.mjs so
actions can import them directly rather than receiving them as arguments.

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

client/conduit.mjs

@@ -0,0 +1,22 @@
+// Conduit client module — import this when using conduit programmatically.
+// Designed for use by Claude or other tools that want to call conduit actions.
+
+const BASE_URL = process.env.CONDUIT_URL || "http://localhost:3015";
+
+export async function callAction(action, params = {}) {
+	const res = await fetch(`${BASE_URL}/action`, {
+		method: "POST",
+		headers: { "Content-Type": "application/json" },
+		body: JSON.stringify({ action, ...params }),
+	});
+	return res.json();
+}
+
+export async function listActions() {
+	return callAction("list-actions");
+}
+
+export async function getQueue() {
+	const res = await fetch(`${BASE_URL}/queue`);
+	return res.json();
+}