Log conversation & suggestive search

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• added conversation log

[AMChierici]

OK, tested and happy to merge, but there are a few improvements to log into issues:

• transitions are better without the white frame, but they feel too fast/abrupt. consider making longer fade-out > fade in even if audio starts already. Though interaction already improved very much.
• question suggested appears only when I deactivate the "interact" mode by clicking on "pause". We should always give both options available simultaneously.
• questions to appear as card and disappear once selected (don't repropose same suggestion again)
• and leave a search bar for searching questions. that's helpful
• helper text in the search bar is going out of the box, and it should state "Type to search available questions".