feat: add archived column to sessions table and isSunday helper

Made-with: Cursor

frontend/src/utils/dateUtils.js

@@ -47,3 +47,12 @@ export function formatLocalDateTime(sqliteTimestamp) {
   return parseUTCTimestamp(sqliteTimestamp).toLocaleString();
 }
 
+/**
+ * Check if a SQLite timestamp falls on a Sunday (in local timezone)
+ * @param {string} sqliteTimestamp
+ * @returns {boolean}
+ */
+export function isSunday(sqliteTimestamp) {
+  return parseUTCTimestamp(sqliteTimestamp).getDay() === 0;
+}
+