0.13.0

## What's Changed
* chore: clean up docs by @carenthomas in https://github.com/letta-ai/letta/pull/3031
* feat: add haiku 4.5 as reasoning model by @AriWebb in https://github.com/letta-ai/letta/pull/3038
* chore: bump version 0.13.0 by @carenthomas in https://github.com/letta-ai/letta/pull/3050

## New Contributors
* @AriWebb made their first contribution in https://github.com/letta-ai/letta/pull/3038

**Full Changelog**: https://github.com/letta-ai/letta/compare/0.12.1...0.13.0