feat(settings): switch built-in weekly tasks per game, and make one your own

The switch sits beside the daily chores and answers the strip's question
too. Built-ins are listed with a link to their dated source. Make it mine
copies one into the reader's tasks, numbers and ticks included, and hides
the original while the copy exists. It's additive, so deleting the copy
brings the original back as it was.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/shared/routines.ts

@@ -103,3 +103,23 @@ export function asOfLabel(day: string): string {
   const [y, m, d] = day.split("-").map(Number);
   return `${d} ${MONTHS[(m ?? 1) - 1]} ${y}`;
 }
+
+/**
+ * A reader's own task copied from a built-in, remembering where it came from.
+ * The copy is theirs to edit; the original stays hidden while it exists.
+ */
+export function mineFrom(routine: Routine): {
+  game: string;
+  title: string;
+  period: Routine["period"];
+  measure: Routine["measure"];
+  from: string;
+} {
+  return {
+    game: routine.game,
+    title: routine.title,
+    period: routine.period,
+    measure: routine.measure,
+    from: routine.id,
+  };
+}