Sending PDF files using the `$builder->with_file()` method is not working.

In a message I posted to the core-ai Slack channel, I wrote:

"Does wp-ai-client support .pdf files via the $builder->with_file( $file_path, $mime_type) method?
When I try this, I get the following message: "No models were found that support text rendering for this request."
Thanks in advance for your help."

In response, @JasonTheAdams posted the change he made here:

https://github.com/WordPress/php-ai-client/pull/161/commits/437d0d978cae73333bfc1c7ccce0337790514873

To test it, I manually added the following code snippets to the OpenAiModelMetadataDirectory and GoogleModelMetadataDirectory files.

[ModalityEnum::text(), ModalityEnum::document()],
[ModalityEnum::text(), ModalityEnum::image(), ModalityEnum::document()],

The "Model not found..." error no longer occurs. However, the error "Unsupported MIME type for inline file message section: "application/pdf" is returned now.

I think a general adjustment regarding file processing is needed.

Here is the Github repo of my project: https://github.com/Arkenon/orchestrator-for-wp-ai-client

Start with OpenAiModelMetadataDirectory and GoogleModelMetadataDirectory, then trace how $builder->with_file() processes MIME types. Reproduce the application/pdf case and follow the existing file-processing path to identify where PDF support is rejected. Done means PDF files no longer produce the unsupported MIME type error for supported models.