I would give it a month tops

Often those sites randomly generate ids and classes, so it will work only once.

F-droid doesn’t just check for reproducibility, they build and sign apps themselves. They don’t take apks from devs, only source code (this also means that F-Droid apks are not compatible with play store apks and can’t be mutually updated die to different signatures. I.e. you can’t install app from play store or directly from dev and update it from f-droid, and vice versa).

They’ve all been in prison

I’m not saying such agreement won’t be reached, I simply don’t believe it will be honored when the time comes. It all rests on the assumption that Putin will be deterred by existence of such guarantees, but he won’t. He will attack Ukraine again, and then what EU gonna do? They will do all they can to weasel out of it in order to avoid aforementioned all-out war. Maybe not by outright refusing, but by stalling, or sending only a token force, etc.

“Supporting Ukraine” by itself is just a sentiment, what matters is actions. And there is no universal agreement on how far Europe should go in that support.

So any Russian incursion would be attacking EU directly.

No, because Ukraine is not a part of EU. Politicians can (and do) debate what exactly “direct attack” means, who was actually at fault and even if the attack was real. Recent sabouteur and hacker attacks against EU countries by Russia have been called a “direct attack on Europe” for example, and many people have been calling for “harsh response” and for Europe to invade and destroy Russia in a curb-stomp battle. Politicians can slither their way out of any agreement, especially with uncertainty of war and Internet giving them ability to influence public opinion through social media.

Security guarantees are meaningless either. European countries would not enter was with Russia with their own soldiers unless directly attacked by Russia. Even if they join some kind of binding security agreement with Ukraine they will find a way to not send their soldiers, and instead provide material/moral support from afar. Mobilization and actual war are extremely unpopular topic in Europe. Any government that sends their soldiers to Ukraine will collapse immediately and outsted by right wing nationalists (the only country that can probably pull it off is Poland).