Add Telegram Bot internal API configuration for Windows deployment

Fix issue where backend cannot communicate with Telegram bot service to save
authentication codes during account linking flow. This caused "link invalid or
expired" errors when users tried to link Telegram accounts.

Changes:
- Add TELEGRAM_BOT_INTERNAL_API environment variable to backend .env.example
  (defaults to http://localhost:8002 for local/Windows deployments)
- Update CLAUDE.md with Telegram Bot integration requirements for Windows
- Add comprehensive troubleshooting guide for Windows deployment at
  deployment/windows/docs/TELEGRAM_BOT_TROUBLESHOOTING.md

The troubleshooting guide includes:
- Diagnostic steps to verify service health and connectivity
- Common issues and solutions (port conflicts, firewall, wrong bot token)
- PowerShell commands for Windows Server administration
- Verification steps for end-to-end testing

This ensures proper backend-to-telegram-bot communication for the auth code
linking workflow in production Windows deployments.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

reports-app/backend/.env.example

@@ -36,4 +36,11 @@ API_PORT=8000
 DEBUG=True
 
 # CORS Configuration
-FRONTEND_URLS=http://localhost:3000,http://localhost:5173
+FRONTEND_URLS=http://localhost:3000,http://localhost:5173
+
+# Telegram Bot Integration
+# Internal API URL for telegram bot service (auth code management)
+# Development (with SSH tunnel): http://localhost:8002
+# Windows Production (local): http://localhost:8002
+# Docker Production: http://telegram-bot:8002
+TELEGRAM_BOT_INTERNAL_API=http://localhost:8002