“Is there any point to which you would wish to draw my attention?”
“To the curious incident of the dog in the night-time.”
“The dog did nothing in the night-time.”
“That was the curious incident,” remarked Sherlock Holmes.
Silver Blaze, in Memoirs of Sherlock Holmes by Sir Arthur Conan Doyle1.
Imagine that there was any kind of information supporting the idea that some of those manifestation were sponsored by a foreign country. Do you think that would have been ignored?
Such an information would have been widely spread:
it would be noteworthy even in a more relaxed political climate.
given the backdrop of intervention by a foreign country, public would be very interested in such an information.
in a more partisan mode, a party or administration that accumulates lots of evidence pointing to foreign interference would be interested in publicizing this as a way to show a moral equivalence.
Now, compare how many unfounded claims were widely spread by several mass media:
members of a political party were involved in a pedophilic organization based in the underground of a pizzeria.
a citizen of the USA was not a citizen of the USA.
the POTUS was lying about his religion.
a presidential candidate put USA uranium reserves under foreign control.
Don't you think that, if there was any proof which could be interpreted as supporting your hypothesis2, that proof would have been already extensively known (especially in this site)? Consider the very low bar that some news organizations have established in order to spread the above examples.
This is no small issue. While the free press (on one hand) and the political attacks on rivals (on the other) can lead to some abuses, it also gives a strong incentive for politicians and other public figures to respect the law3.
It also allows me to confidently say, for example, that there is absolutely no evidence that Mr. Trump is a were-rabbit who transforms each full moon; as any available evidence available pointing to that would be immediately public knowledge.
So, while it is hard to prove a negative (which is, I guess, exactly the reason of why the OP has posted the question) it is pretty easy to see that, in fact, the dog has not (so far) barked.
That said, and tangentially related to your question, there is evidence that the Russian campaign in social networks supported some anti-Trump movements, like Black Lives Matter. As can be expected from my explanations, those evidences have been reported by the press; the general consensus seem to be that the aim was to increase polarization to help more radical candidates. Still that is a long shot from "organizing anti-Trump demonstrations".
No, I did not read it. But it was mentioned in a CSI: Las Vegas
2Note that I do not talk about "evidence beyond doubt". The previous examples clearly note that the standard to spread such information can be rather low.
3In the very improbable case that some politician happens not to be a completely honest and ethical human being.