v0.2.7

Bump version to 0.2.7 and enhance cross-file context for NES predictions

Implemented cross-file recent change tracking and document context for the Next-Edit Suggestion (NES) engine. This allows the model to better understand edits spanning multiple files by passing relevant file chunks and diffs into the prompt.

- **Core**: Updated `engine.rs` and `prompt.rs` to compute and include `cross_file_recent_changes` and `cross_file_chunks` in the sweep prompt.
- **VS Code**: Enhanced `ApiClient` and `DocumentTracker` to track and provide content for external files involved in recent edits.
- **Version**: Bumped version to `0.2.7` in both IntelliJ and VS Code manifests.