I think some people are being way to optimistic on the Algeria situation.
For one despite Algeria effectively being a colony, it is legally and some what emotionally a core territory of France in this era. It's not an official colonial holding as such, but considered a part of France proper. This is why in the original time line the fight over it was particularly brutal and the 4th French Republic fell over it, to be replaced by the 5th led by a ww2 general.
Secondly, all one needs to win is to covertly keep moving weapons to Algeria and other colonial areas. As the main long term issue that is making these places unsustainable is that their population growth versus France is far higher. So the once very large power imbalance is becoming ever less so. France in time will lose its grip, especially if they get some level of armaments over time as well. As such the USSR already has a victory, that's pretty much guaranteed. After all in the end what people will remember is who was the final winner, did the colonies come free in the end or not? Particular stand offs have little long term prestige effects and thus are more a question of are they a risk worth taking.
As such these responses as such are more a form of how one achieves ones victory, or alternately, how one might still clutch defeat from the jaws of victory.
Based on the above points, what you're currently looking at has probably more similarities with the Cuba crisis then one might really like. For instance freedom of shipping through international waters is indeed a right, but this didn't stop the USA from blockading Cuba. And we know now from the declassified materials from the USSR and USA that if that blockade had been run escalation to full scale nuclear war was very much present. At the very least the USA would definitely have shot at any ship trying to force it. And this was due to a perceived threat to their core territory, the USA proper as such. The same thing as France has right now, rightly or wrongly they probably very much perceive this as an attack on France proper. If you'd done it at one of the other colonies it would be a different matter, but Algeria is thus due to this an exception.
So arming Libya has a very real risk of French intervention and a shooting war and I really don't think you should underestimate the potential of French willingness to blockade fleets shipping weapons that are going to be used to attack France proper.
This is definitely nuclear brinkmanship on a nation that is feeling increasingly surrounded on all sides by a hostile power, which now seems intent on taking actual French core territories now. Put the fleet there and they could also interpret it as the end is nigh. That once their encirclement is near complete European France will be next.
Personally I don't think this is worth it really as such, the loss if it did go nuclear would be extreme, the USSR might well collapse, communism may well end. On the other side is colony that if you support it a bit more surreptitiously is ultimately still going to win, just like it did in OTL. So I'm not seeing any kind of long term value from direct confrontation. If it affected the USSR directly it would be a different matter, but trying to push a country on a core territory issue seems highly problematic to me. Even if you some how one it, the global repercussions would not be good, lots of countries would fully align against the USSR for the perceived risk of direct attacks on their countries.
If one has to risk risk nuclear brinkmanship, better on something else that is less core to one of the countries involved. That way you'd have more options for deescalation still.