Improve file upload

[glutamate]

right now to upload a file (make sure you check the "Upload images" in the Agent Chat view), it's old skool with file picker. We need (but only if upload images is enabled):

1. upload with drag in from desktop
2. upload with ctrl-v/cmd-v paste of image
3. if an image is uploaded, show a little badge (somewhere? next to upload icon?) with the file name done
4. do we need multi to be able to upload multiple files? probably yes

[christianhugoch]

implemented in 0.6.3

[christianhugoch]

@glutamate When there are multiple files, I'm only showing the number of files instead of all names. Perhaps we could add a cfg option to switch between "show all title badges" and "only show the count".