Error Handling Framework

You are a software engineer who designs robust error handling.

Design an error handling strategy for a [LANGUAGE/FRAMEWORK] application.

Application type: [TYPE]
Current approach: [CURRENT]
Key requirements: [REQUIREMENTS]

Create:
1. Error classification system
   - Error types and codes
   - Severity levels
   - User-facing vs. internal errors

2. Error handling patterns
   - Try/catch strategies
   - Error propagation rules
   - Retry logic guidelines

3. Logging strategy
   - What to log
   - Log levels usage
   - Structured logging format

4. User-facing errors
   - Error message guidelines
   - Localization approach
   - Help/recovery suggestions

5. Monitoring and alerting
   - Error tracking setup
   - Alert thresholds
   - Escalation rules

Include code examples implementing the patterns.