CAS service unreachable: cas-server.xethub.hf.io returns Hostpoint configuration error

### Bug

Docling fails during PDF extraction with a **CAS service error**, even when OCR is disabled.
After investigation, the domain `https://cas-server.xethub.hf.io` (used internally by Docling) appears to be **misconfigured or offline** — it returns a Hostpoint “Configuration Error” page instead of a valid HTTPS endpoint.

Error message:
RuntimeError: Data processing error: CAS service error : ReqwestMiddleware Error: Request failed after 5 retries

---

### Steps to reproduce

1. Run a PDF extraction with:
```python
from docling.datamodel.pipeline_options import PdfPipelineOptions
pipeline_options = PdfPipelineOptions(
do_ocr=False,
do_table_structure=True,
)

2. Call DocumentConverter().convert()

3. Docling tries to reach https://cas-server.xethub.hf.io

4. After 5 retries (~60 seconds), it fails with the CAS error

Network test results:
curl -v --max-time 10 https://cas-server.xethub.hf.io
* subjectAltName does not match hostname cas-server.xethub.hf.io
* SSL: no alternative certificate subject name matches target hostname

#### Browser output:

“Erreur de configuration – The website you are trying to access is not available (Hostpoint.ch)”

This shows that cas-server.xethub.hf.io is no longer responding correctly.

### Docling version
Python 3.13
2.58.0