CLI export doesn't work for text

Using the CLI export doesn't render text layers.

Steps to reproduce:
1. Make a new document in the latest web version of Graphite with `cargo run`.
2. Using the text tool, add some text to say "Test"
3. Save this file to the computer as `my_document.graphite` in your document folder
4. Export this file through the CLI with `cargo run cli -- export ~/Documents/my_document.graphite -o my_output.png --width 1920 --height 1080`
5. Observe that the resulting image is blank (or, if you had another layer in the artboard, the result is that other layer)

Other notes:
- This seems to be an issue for any of the 4 filetypes (png, jpg, svg, gif)
- I tried some workarounds, like converting the text to sample polyline or filling it with instance points, and these would also not render, so my guess is the Text node itself has some kind of issue.
- Unfortunately, I wasn't able to track down when this started, as the introduction of this bug goes beyond the current CLI syntax.

使用文档中的 `cargo run cli -- export` 命令重现该故障，然后跟踪 CLI 导出路径以及它如何处理 Text 节点。将包含文本的文档导出为 PNG、JPG、SVG 和 GIF，并验证文本能够渲染，以确认修复有效。

由索引模型根据 Issue 内容生成。