feat: repo viewer (#14)

* feat: repo viewer WIP

* refactor: restructure file viewer and tree layout components

- Removed the old tree layout component and replaced it with a new viewer structure that includes blob and tree views.
- Introduced a new breadcrumb component for better navigation within the repository.
- Added a branch selector for switching between branches in the viewer.
- Implemented a raw file view for direct access to file contents.
- Enhanced the blob component to handle binary and markdown files with appropriate rendering.
- Integrated a button group for actions like downloading and copying file content.
- Updated the styling and structure of the components for improved usability and consistency.
- Added support for variable font loading in the root route.

* fix: handle blob content serialization and implement caching for tree and blob retrieval

* feat: add support for ".git" and improve UI for "code" tab

* coderabbit: some improvemented