refactor(core): dedupe shared config and runtime helpers

src/plugin-sdk/tool-send.ts

@@ -0,0 +1,15 @@
+export function extractToolSend(
+  args: Record<string, unknown>,
+  expectedAction = "sendMessage",
+): { to: string; accountId?: string } | null {
+  const action = typeof args.action === "string" ? args.action.trim() : "";
+  if (action !== expectedAction) {
+    return null;
+  }
+  const to = typeof args.to === "string" ? args.to : undefined;
+  if (!to) {
+    return null;
+  }
+  const accountId = typeof args.accountId === "string" ? args.accountId.trim() : undefined;
+  return { to, accountId };
+}