fix(tlon): Fix Zod v4 record() and @urbit/aura v3 API changes (#1631)

* fix(tlon): Fix Zod v4 record() and @urbit/aura v3 API changes

- Fix Zod v4.3.6 bug: single-arg z.record() fails with toJSONSchema()
  - Use two-arg form: z.record(z.string(), schema)
  - Fixes 'Cannot read properties of undefined (reading _zod)' error

- Fix @urbit/aura v3.0.0 API migration:
  - unixToDa() → da.fromUnix()
  - formatUd() → scot('ud', ...)
  - Fixes '(0 , _aura.unixToDa) is not a function' error

These were blocking Tlon plugin loading and outbound messaging.

* fix: add tlon schema/aura tests (#1631) (thanks @arthyn)

---------

Co-authored-by: Peter Steinberger <steipete@gmail.com>

extensions/tlon/src/urbit/send.ts

@@ -1,4 +1,4 @@
-import { unixToDa, formatUd } from "@urbit/aura";
+import { scot, da } from "@urbit/aura";
 
 export type TlonPokeApi = {
   poke: (params: { app: string; mark: string; json: unknown }) => Promise<unknown>;
@@ -14,7 +14,7 @@ type SendTextParams = {
 export async function sendDm({ api, fromShip, toShip, text }: SendTextParams) {
   const story = [{ inline: [text] }];
   const sentAt = Date.now();
-  const idUd = formatUd(unixToDa(sentAt));
+  const idUd = scot('ud', da.fromUnix(sentAt));
   const id = `${fromShip}/${idUd}`;
 
   const delta = {