feat: display truncated lightning address for winners

- Add truncateLightningAddress utility (shows first 2 chars + ******)
- Backend: Include winner_address in past-wins API response
- Frontend: Display truncated address in past winners list
- Telegram: Add truncated address to draw announcements for transparency

Example: username@blink.sv -> us******@blink.sv

telegram_bot/src/messages/index.ts

@@ -464,11 +464,13 @@ Good luck next round! 🍀`,
       winnerName: string,
       winningTicket: string,
       prizeSats: string,
-      totalTickets: number
+      totalTickets: number,
+      winnerAddress?: string
     ) =>
       `🎰 *JACKPOT DRAW COMPLETE!* 🎰
 
 🏆 *Winner:* ${winnerName}
+⚡ *Address:* \`${winnerAddress || 'N/A'}\`
 🎟 *Winning Ticket:* #${winningTicket}
 💰 *Prize:* ${prizeSats} sats
 📊 *Total Tickets:* ${totalTickets}

telegram_bot/src/services/notificationScheduler.ts

@@ -6,6 +6,7 @@ import { logger } from './logger';
 import { messages } from '../messages';
 import { GroupSettings, reminderTimeToMinutes, formatReminderTime, ReminderTime, DEFAULT_GROUP_REMINDER_SLOTS } from '../types/groups';
 import { TelegramUser } from '../types';
+import { truncateLightningAddress } from '../utils/format';
 
 interface CycleInfo {
   id: string;
@@ -158,6 +159,7 @@ class NotificationScheduler {
     let winnerDisplayName = 'Anon';
     let winnerTicketNumber = '0000';
     let winnerTelegramId: number | null = null;
+    let winnerLightningAddress = '';
     let potSats = 0;
     let prizeSats = 0;
     let payoutStatus = 'processing';
@@ -174,6 +176,7 @@ class NotificationScheduler {
             const user = await stateManager.getUser(telegramId);
             winnerTelegramId = telegramId;
             winnerDisplayName = user ? stateManager.getDisplayName(user) : 'Anon';
+            winnerLightningAddress = status.purchase.lightning_address || '';
             
             const winningTicket = status.tickets.find(t => t.is_winning_ticket);
             if (winningTicket) {
@@ -240,7 +243,8 @@ class NotificationScheduler {
       winnerDisplayName, 
       winnerTicketNumber, 
       potSats,
-      uniqueUserCount
+      uniqueUserCount,
+      winnerLightningAddress
     );
   }
 
@@ -252,11 +256,13 @@ class NotificationScheduler {
     winnerDisplayName: string,
     winnerTicketNumber: string,
     potSats: number,
-    totalParticipants: number
+    totalParticipants: number,
+    winnerLightningAddress: string
   ): Promise<void> {
     if (!this.bot) return;
 
     const groups = await groupStateManager.getGroupsWithFeature('drawAnnouncements');
+    const truncatedAddress = truncateLightningAddress(winnerLightningAddress);
     
     for (const group of groups) {
       try {
@@ -264,7 +270,8 @@ class NotificationScheduler {
           winnerDisplayName,
           `#${winnerTicketNumber}`,
           potSats.toLocaleString(),
-          totalParticipants
+          totalParticipants,
+          truncatedAddress
         );
         
         await this.bot.sendMessage(group.groupId, message, { parse_mode: 'Markdown' });
@@ -384,6 +391,7 @@ class NotificationScheduler {
     let winnerDisplayName = 'Anon';
     let winnerTicketNumber = '0000';
     let winnerTelegramId: number | null = null;
+    let winnerLightningAddress = '';
     let prizeSats = 0;
     let payoutStatus = 'processing';
 
@@ -397,6 +405,7 @@ class NotificationScheduler {
             const user = await stateManager.getUser(telegramId);
             winnerTelegramId = telegramId;
             winnerDisplayName = user ? stateManager.getDisplayName(user) : 'Anon';
+            winnerLightningAddress = status.purchase.lightning_address || '';
             
             const winningTicket = status.tickets.find(t => t.is_winning_ticket);
             if (winningTicket) {
@@ -458,7 +467,7 @@ class NotificationScheduler {
 
     // Send group announcements
     const uniqueUserCount = userPurchases.size;
-    await this.sendGroupDrawAnnouncements(cycle, winnerDisplayName, winnerTicketNumber, uniqueUserCount);
+    await this.sendGroupDrawAnnouncements(cycle, winnerDisplayName, winnerTicketNumber, uniqueUserCount, winnerLightningAddress);
   }
 
   /**
@@ -468,11 +477,13 @@ class NotificationScheduler {
     cycle: CycleInfo,
     winnerDisplayName: string,
     winnerTicketNumber: string,
-    totalParticipants: number
+    totalParticipants: number,
+    winnerLightningAddress: string
   ): Promise<void> {
     if (!this.bot) return;
 
     const groups = await groupStateManager.getGroupsWithFeature('drawAnnouncements');
+    const truncatedAddress = truncateLightningAddress(winnerLightningAddress);
     
     for (const group of groups) {
       const delay = (group.announcementDelaySeconds || 0) * 1000;
@@ -483,7 +494,8 @@ class NotificationScheduler {
             winnerDisplayName,
             `#${winnerTicketNumber}`,
             cycle.pot_total_sats.toLocaleString(),
-            totalParticipants
+            totalParticipants,
+            truncatedAddress
           );
           
           if (this.bot) {

telegram_bot/src/utils/format.ts

@@ -125,4 +125,20 @@ export function truncate(str: string, maxLength: number): string {
   return str.substring(0, maxLength - 3) + '...';
 }
 
+/**
+ * Truncate lightning address for privacy
+ * "username@blink.sv" -> "us******@blink.sv"
+ */
+export function truncateLightningAddress(address: string): string {
+  if (!address || !address.includes('@')) return address;
+  
+  const [username, domain] = address.split('@');
+  
+  // Show first 2 chars of username, then asterisks
+  const visibleChars = Math.min(2, username.length);
+  const truncatedUsername = username.substring(0, visibleChars) + '******';
+  
+  return `${truncatedUsername}@${domain}`;
+}
+