Fix Railway deployment crashes: hardened token validation, HTTP health server, and comprehensive documentation

[Copilot]

Problem

Railway deployments were failing with multiple critical issues:

1. Service crashes: Using python bot_runner.py as start command only runs the bot without binding to Railway's required $PORT, causing Railway to mark the service as CRASHED even when the bot works
2. Token validation errors: telegram.error.NetworkError: InvalidURL("Invalid non-printable ASCII character in URL, '\n' at position 74.") caused by TELEGRAM_TOKEN containing trailing newlines or spaces
3. Compilation errors: st.warning called before importing streamlit in app.py, and indentation errors in config.py
4. Missing deployment configuration: No railway.toml, .env.example, or proper README documentation

Solution

Railway-Compatible Architecture

Replaced the existing main.py with a Railway-compatible entry point that:

• Serves HTTP health checks on 0.0.0.0:$PORT (required by Railway)
• Runs the Telegram bot concurrently in a background thread
• Keeps the service healthy even if the bot fails due to token issues

# New main.py architecture
HTTP Health Server (Port $PORT) → ✅ Railway sees healthy service
Telegram Bot (Background Thread) → 🤖 Processes messages independently

Hardened Token Validation

Enhanced bot.py with robust token validation:

def validate_telegram_token(token):
    if not token:
        return False, "TELEGRAM_TOKEN not found in environment variables!"
    
    # Critical fix: strip whitespace and newlines
    token = token.strip()
    
    # Validate Telegram token format
    pattern = r'^\d{8,10}:[a-zA-Z0-9_-]{30,}$'
    if not re.match(pattern, token):
        return False, f"Invalid TELEGRAM_TOKEN format. Expected: digits:hash"
    
    return True, token

This prevents the InvalidURL errors caused by tokens with trailing newlines copied from environment variable settings.

Configuration as Code

Added railway.toml for consistent deployments:

[deploy]
startCommand = "python main.py"
restartPolicyType = "ON_FAILURE"
restartPolicyMaxRetries = 3

Comprehensive Documentation

Created a complete README.md (5600+ characters) covering:

• One-click Railway deployment with deploy button
• Local development setup with .env.example template
• Troubleshooting guide addressing the specific newline token issue
• Environment variable configuration table
• Architecture diagrams and deployment flow

Key Improvements

Stability: Service stays healthy on Railway regardless of bot token issues
Error Handling: Clear logging with actionable troubleshooting messages
Developer Experience: Complete documentation and local development template
Maintainability: Configuration as code prevents deployment drift

Testing

Validated the solution with comprehensive tests:

• ✅ Token validation correctly strips newlines and validates format
• ✅ Health server responds on / and /health endpoints returning service status
• ✅ Invalid tokens are logged clearly without crashing the web service
• ✅ Railway deployment configuration works as expected

The fix addresses all reported issues while maintaining backward compatibility and adding robust error handling for production deployments.

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