Root cause: ensure_ocr_languages_from_settings() only downloaded tessdata
when the 'tesseract' provider was active, but embed_text_layer() uses
ocrmypdf (which needs tessdata) as a fallback for ALL OCR providers.
- embed_text_layer(): call ensure_tesseract_languages(language) after
confirming ocrmypdf is on PATH, so language data is present before
ocrmypdf is invoked (prevents exit code 3 for fra/deu/etc.)
- ensure_ocr_languages_from_settings(): extend the condition from
'tesseract' in active_providers to also trigger when ocrmypdf is
on PATH, enabling proactive pre-download at startup for any config
- Tests: mock shutil.which and ensure_tesseract_languages in affected
test cases; rename azure-only test and add new test for ocrmypdf case
Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
- PDFs are now uploaded to Mistral Files API (POST /v1/files) and
processed via a signed document_url, resolving the 422 error caused
by passing data:application/pdf;base64,... to an image endpoint
- Images (JPEG/PNG/GIF/WEBP/BMP/TIFF) use base64 image_url directly
- Unsupported MIME types raise a clear ValueError
- Magic-byte fallback detects PDFs with no file extension
- Switches from openai chat completions to requests HTTP calls
- Adds helper method _upload_pdf_and_get_document()
- Adds TestMistralOCRProvider with 9 unit tests covering all paths
Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>