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

telegram_bot/botfather_commands.txt

@@ -0,0 +1,71 @@
+================================
+BOTFATHER COMMAND SETUP
+================================
+
+Send to @BotFather: /setcommands
+Then select your bot and paste the commands below:
+
+================================
+PRIVATE CHAT COMMANDS
+================================
+
+start - Start the bot and register
+lottomenu - Show main menu
+buyticket - Buy lottery tickets
+tickets - View your tickets
+wins - View your wins
+lottoaddress - Set your Lightning Address
+lottosettings - Notification settings
+lottohelp - Show help
+jackpot - Show current jackpot
+
+================================
+GROUP COMMANDS (Optional)
+================================
+
+If you want separate commands for groups, use /setcommands again
+and select "Edit commands for groups":
+
+jackpot - Show current jackpot info
+lottosettings - Configure lottery settings (admin only)
+lottohelp - Show help and commands
+
+================================
+BOT DESCRIPTION
+================================
+
+Send to @BotFather: /setdescription
+
+Lightning Lotto - Win Bitcoin on the Lightning Network! ⚡
+
+Buy lottery tickets with Lightning, get instant payouts if you win.
+• Buy tickets with sats
+• Set your Lightning Address for payouts
+• Get notified about draws and wins
+• Join groups to get jackpot alerts
+
+================================
+ABOUT TEXT
+================================
+
+Send to @BotFather: /setabouttext
+
+⚡ Lightning Lotto Bot ⚡
+
+A provably fair Bitcoin lottery powered by the Lightning Network.
+
+🎟️ Buy tickets with Lightning
+💰 Instant payouts to your Lightning Address
+🔔 Draw reminders & win notifications
+👥 Group support with announcements
+
+Start with /start to begin!
+
+================================
+SHORT DESCRIPTION
+================================
+
+Send to @BotFather: /setshortdescription
+
+Win Bitcoin on the Lightning Network! Buy lottery tickets, get instant payouts. ⚡
+