Implement three divination modes, learn pages, and PM2 deploy on port 3130.

Add liuyao/bazi/combined flows with shared calc and AI infrastructure, 64-gua learn routes, and update Ubuntu PM2 deployment docs for port 3130.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/calc/time.ts

@@ -0,0 +1,29 @@
+/** 中国标准时间基准经度（UTC+8） */
+export const CHINA_STANDARD_MERIDIAN = 120;
+
+/**
+ * 根据出生地经度校正真太阳时。
+ * 每差 1 度经度，时间差约 4 分钟。
+ */
+export function adjustToTrueSolarTime(
+  date: Date,
+  longitude: number,
+  standardMeridian = CHINA_STANDARD_MERIDIAN,
+): Date {
+  const offsetMinutes = (longitude - standardMeridian) * 4;
+  return new Date(date.getTime() + offsetMinutes * 60 * 1000);
+}
+
+export function formatDateTime(date: Date): string {
+  const pad = (n: number) => n.toString().padStart(2, "0");
+  return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(date.getDate())} ${pad(date.getHours())}:${pad(date.getMinutes())}`;
+}
+
+export function parseDateTime(
+  dateStr: string,
+  timeStr: string,
+): Date {
+  const [year, month, day] = dateStr.split("-").map(Number);
+  const [hour, minute] = timeStr.split(":").map(Number);
+  return new Date(year, month - 1, day, hour, minute, 0);
+}