Improve Vim keybinding UX and fix minor bugs

Features and fixes to be implemented:

~traverse thread delimiters (moving with arrows or j and k gets stuck upon reaching a "View full thread" element)~
press Esc to unfocus post
use arrows to choose how to repost (simple repost or quote post) + Esc to cancel the choice modal
use Tab and side arrows to switch between tabs on main ("Following" and "What's hot")
mute threads and accounts from keyboard
pause Vim keybindings when any modal appears (including "show help")
~remove the browser focus outline and make Enter work again~

xenohunter / bluesky-overhaul