fix: add ttl field to TaskResource zod schema to prevent silent stripping

Author: nicktrn

packages/core/src/v3/schemas/resources.ts

@@ -13,6 +13,7 @@ export const TaskResource = z.object({
   triggerSource: z.string().optional(),
   schedule: ScheduleMetadata.optional(),
   maxDuration: z.number().optional(),
+  ttl: z.string().or(z.number().nonnegative()).optional(),
   // JSONSchema type - using z.unknown() for runtime validation to accept JSONSchema7
   payloadSchema: z.unknown().optional(),
 });