* feat: update FileReadTool description to mention image and PDF support
Add explicit mention of image (OCR) and PDF (text extraction) support
to the FileReadTool description for better discoverability.
* feat: update FileReadTool description to include support for docx and epub files; change base64 decoding to utf-8
* feat: enhance ToolLoopAgentRunner to support image and audio modalities; add context sanitization logic