add draft warning about post visibility

[ratsclub]

This introduces a small textual warning regarding draft visibility.

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[sirodoht]

Thanks! This is great! I have some reservations about the design. I'll get back to you when I look better into it!

[ratsclub]

One idea, instead of adding this huge warning, we add a Share link/Copy link to the button action. What do you think?

[sirodoht]

Hmm interesting. Yeah, that could be better. But we would need JavaScript to copy it. Maybe we could have a non-JavaScript option as well.

[thiagokokada]

IMO, I think I prefer the first solution since share link is still not clear what is happening (and also I don't think this feature needs to depend on JavaScript).

However one thing, I think that the warning should only appear for logged in users (or even better, only for the author). For whatever who receives the link, they don't need to care about this detail.