feat: implement Weather Workshop feature with models, UI components, and session management for enhanced team visibility and personal well-being tracking

src/lib/date-utils.ts

@@ -0,0 +1,21 @@
+/**
+ * Get ISO week number for a given date
+ * ISO 8601 week numbering: week starts on Monday, first week contains Jan 4
+ */
+export function getISOWeek(date: Date): number {
+  const d = new Date(Date.UTC(date.getFullYear(), date.getMonth(), date.getDate()));
+  const dayNum = d.getUTCDay() || 7;
+  d.setUTCDate(d.getUTCDate() + 4 - dayNum);
+  const yearStart = new Date(Date.UTC(d.getUTCFullYear(), 0, 1));
+  return Math.ceil(((d.getTime() - yearStart.getTime()) / 86400000 + 1) / 7);
+}
+
+/**
+ * Get week number and year for a given date
+ * Returns format: "S06-2026"
+ */
+export function getWeekYearLabel(date: Date = new Date()): string {
+  const week = getISOWeek(date);
+  const year = date.getFullYear();
+  return `S${week.toString().padStart(2, '0')}-${year}`;
+}