Zed v1.19.0-pre: Call Hierarchy, AI & Git Enhancements

Zed v1.19.0-pre introduces call hierarchy support, multi-select in the Git Panel, and automatic language detection for untitled buffers, enhancing code navigation and version control workflows. It also brings significant AI improvements, including support for OpenRouter models, Claude Fable 5.1, and better streaming for OpenAI-compatible providers, alongside new tabular data previews.