Added Russian Olympiad papers, KOR math, Roy & Clarke, and Kevin Zhou mechanics handouts to the drive

Quick resource drop for today. Just added a bunch of higher-level math and physics stuff to the vault:

• Math: KOR (Korean) and Russian Olympiad past papers with translated problem sets, plus a clean PDF of Roy & Clarke.
• Physics: Kevin Zhou’s physics handouts for Mechanics (probably the cleanest breakdown of advanced physics topics available right now).

Still adding new stuff daily as I work through problem sets. Everything is sitting in #resource-vault on our server (The Euler-Maxwell Network).
https://discord.gg/3CXj2JC4fX