Technique labels everywhere

Technique labels

More submissions get a label. About one in twenty accepted submissions showed no technique at all, often a textbook BFS or two-pointer solution that fell just short of the confidence bar. The bar for a problem's own techniques is a little lower now, and when the classifier still can't settle on one, a second model looks at the code and picks. Built-in one-liners still stay unlabeled.
Complexity always shows. A submission without a technique used to hide its time and space complexity too. The complexity now shows on its own.
No reload needed. A fresh accepted submission keeps checking for its label for a few seconds, so a late pick appears without refreshing the page.
Study groups. The expanded solution list on a room's Leaderboard tab and each problem's solutions on the results page now show technique chips under each solution.

Improvements to User Contribution flow.
Hidden email. Opening Settings on stream used to put your email address on screen. The Account section now shows a mask with a Show button, and every visit starts hidden.
New emotes. Thirteen animated emotes join chat, covering coding, taking notes, popcorn moments, hype and goodbyes: HACKERMANS, peepoTyping, COGGERS, Nerdge, monkaHmm, peepoNoted, MJPopcorn, pogSlide, peepoCheer, WICKED, peepoGiggles, peepoExit and Reggae.

Full C# stack traces. A C# runtime error used to drop every framework frame and name your file differently from a compile error, so you couldn't see which library call threw. The trace now keeps every frame, Dictionary.get_Item included, and your own frames read main.cs:line N at the line in the editor.
Rename Python parameters freely. Python solutions were called with keyword arguments, so renaming a parameter in the starter failed with "got an unexpected keyword argument". Arguments are now passed by position, like every other language.
Reported problems. Six problems got fixes from your reports: two moved up a tier and one moved down, one statement now says the chosen indices don't have to be next to each other, and two test suites gained cases that stop slow or shortcut solutions from passing.