Add comprehensive network error handling and recovery mechanisms

# Build robust error handling for various network failure scenarios:

Error Handling Features:

1. Error Classification
- Network vs server errors
- Temporary vs permanent failures
- User-recoverable vs system errors
- Security vs connectivity issues
2. Recovery Strategies
- Automatic retry with backoff
- Fallback endpoint usage
- Cached response fallback
- Manual user intervention
3. User Communication
- Context-aware error messages
- Recovery action suggestions
- Progress indication during recovery
- Escalation to human support

The issue names no files, tests, or entry points, so first locate the SDK's network request and error-handling code. Define the supported failure classifications and recovery behavior before implementation; done means retries, fallback paths, user guidance, and escalation behavior are covered for the listed scenarios.

Written by the indexing model from the issue text.