fix: show creator as clickable user link without pinging

Changed from @user#1663194938 to using tg://user?id=XXX link format.
This creates a clickable link to the user's DM without sending a ping.

apps/telegram-bot/commands.py

@@ -661,8 +661,7 @@ async def cmd_show(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         due_str = dt_due.strftime("%d %B %Y %H:%M")
         lines.append(f"📅 {due_str} ({timezone_str})")
 
-    username = bounty.created_by_username or f"user#{bounty.created_by_user_id}"
-    lines.append(f"👤 @{username}")
+    lines.append(f"👤 [User](tg://user?id={bounty.created_by_user_id})")
 
     dt_created = datetime.fromtimestamp(bounty.created_at, tz=tz)
     created_str = dt_created.strftime("%Y-%m-%d %H:%M")