Add async retry decorator with exponential backoff to handle transient network connection errors (httpx.ConnectError) when connecting to turbopuffer.com. This addresses production errors seen in memgpt-server. Changes: - Add `async_retry_with_backoff()` decorator for async methods - Add `is_transient_error()` helper to identify retryable errors - Apply retry logic to all turbopuffer network operations - Retry config: 3 retries, 1s initial delay, 2x backoff, 10% jitter Fixes #8390 Relates to #8155 🤖 Generated with [Letta Code](https://letta.com) Co-authored-by: letta-code <248085862+letta-code@users.noreply.github.com> Co-authored-by: datadog-official[bot] <datadog-official[bot]@users.noreply.github.com> Co-authored-by: Kian Jones <11655409+kianjones9@users.noreply.github.com>