More UI updates

Continuing to clarify and polish the interface.

• There is now an “essence meter” to make it more visually clear when you gain or lose essence.
• The “release soul” prompt now has its own clearer UI, rather than being a log message.
• In the target info view, you can now see whether the target is injured.

This should be the last UI-heavy update. I’m switching focus to gameplay now. First up is balancing the slow effect, which is still OP despite previous attempts to balance it. I’m also adding some more soul effects and introducing randomized effects (i.e., eye monsters will have randomly generated soul effects from an eye monster pool, versus every tier always having the same effects).