* Add pdfjs for reading PDF files.
* Upgrade various dependeny minor versions.
* Add chat button to source action bar.
* Add chat model selector in chat toolbar.
* chore: bump dependencies
* feat(Chat): provide a list of local file types that can be read for chat purposes (PDF and plain text file types).
* feat(Chat): Implement online PDF and local file processing for use in Chat. Dramatically improved the ability to summarize, especially larger documents.
* chore: Remove unused functions but keep stubs for later use.
* fix: a bug where theme settings were not saved to file correctly.