Fix reminder scheduling and add group features

- Fix reminder duplicate bug: use slot-only keys to prevent multiple reminders when settings change
- Add New Jackpot announcement delay setting for groups (default 5 min)
- Cancel unpaid purchases after draw completes (prevents payments for past rounds)
- Add BotFather commands template file
- Update README documentation

back_end/src/scheduler/index.ts

@@ -242,6 +242,8 @@ async function checkAndExecuteDraws(): Promise<void> {
     for (const cycle of result.rows) {
       console.log(`Executing draw for cycle ${cycle.id} (${cycle.cycle_type})`);
       await executeDraw(cycle.id);
+      // Cancel unpaid invoices for this cycle after draw
+      await cancelUnpaidPurchases(cycle.id);
     }
 
   } catch (error) {
@@ -249,6 +251,30 @@ async function checkAndExecuteDraws(): Promise<void> {
   }
 }
 
+/**
+ * Cancel unpaid purchases after a draw completes
+ * This prevents payments for invoices from past rounds
+ */
+async function cancelUnpaidPurchases(cycleId: string): Promise<void> {
+  try {
+    const result = await db.query(
+      `UPDATE ticket_purchases 
+       SET status = 'cancelled', updated_at = NOW()
+       WHERE cycle_id = $1 
+       AND status = 'pending'
+       RETURNING id`,
+      [cycleId]
+    );
+
+    const cancelledCount = result.rows.length;
+    if (cancelledCount > 0) {
+      console.log(`Cancelled ${cancelledCount} unpaid purchases for cycle ${cycleId}`);
+    }
+  } catch (error) {
+    console.error('Error cancelling unpaid purchases:', error);
+  }
+}
+
 /**
  * Update cycles to 'sales_open' status when appropriate
  */