Remove BTCPay completely, integrate SilverPAY only, configure TeleBot with real token

- Removed all BTCPay references from services and configuration
- Implemented SilverPAY as sole payment provider (no fallback)
- Fixed JWT authentication with proper key length (256+ bits)
- Added UsersController with full CRUD operations
- Updated User model with Email and Role properties
- Configured TeleBot with real Telegram bot token
- Fixed launchSettings.json with JWT environment variable
- E2E tests passing for authentication, catalog, orders
- Payment creation pending SilverPAY server fix

🤖 Generated with Claude Code

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

TeleBot/TeleBot/appsettings.json

@@ -9,8 +9,8 @@
     "Comment": "This will be populated after first registration with admin panel"
   },
   "Telegram": {
-    "BotToken": "",
-    "AdminChatId": "",
+    "BotToken": "8496279616:AAE7kV_riICbWxn6-MPFqcrWx7K8b4_NKq0",
+    "AdminChatId": "123456789",
     "WebhookUrl": "",
     "UseWebhook": false,
     "Comment": "Bot token will be fetched from admin panel API if BotManager:ApiKey is set"