Hm, so with both the WoWS folder and the installer listed as AV exceptions and both given admin privileges it still doesn't work. Only the harbor drydock mod is showing up, and that's as a blank "image" which for all intents and purposes freezes the game when I try to switch to it. After setting it as my harbor, the interface animations still work (cursor moves and I can select other harbors), but it's impossible to leave the harbor select screen or set it to a different harbor, almost like it's trying eternally to load something that it's unable to find before allowing the game to continue. Very strange.
I get the feeling there's some really simple "turn it off and back on again"-style solution to this and I'll feel like an idiot afterward for not having thought of it. Anyway, I'll see if there's anything else on my end that could be causing it and if nothing else works try a full reinstall. Thanks for helping narrow it down.
EDIT: It works after a reinstall. That unfortunately doesn't answer the question of why it didn't work before, but at least it's functional.