Simplify Threads captions and capture five minutes after sunrise

server/threads/publisher.ts

@@ -7,7 +7,11 @@ import { THREADS } from '../../src/constants/threads.ts';
 export function dailySchedule(now: Date) {
   const sunrise = calculateSun(now, observer).sunrise;
   if (!sunrise || !Number.isFinite(+sunrise)) throw new Error('No sunrise for this date');
-  return { date: kstFields(now).date, sunrise, prepareAt: new Date(+sunrise - THREADS.prepareMs) };
+  return { date: kstFields(now).date, sunrise, captureAt: sunriseCaptureTime(sunrise), prepareAt: new Date(+sunrise - THREADS.prepareMs) };
+}
+
+export function sunriseCaptureTime(sunrise: Date): Date {
+  return new Date(+sunrise + THREADS.captureDelayMs);
 }
 
 export async function threadsRequest(token: string, path: string, params: Record<string, string>, method = 'GET', request: typeof fetch = fetch) {