Add theme-set/switching logic, and minor nvim, tmux, obsidian changes

src_files/.local/scripts/theme-update-terminal

@@ -0,0 +1,18 @@
+#!/bin/zsh
+
+theme_update_havoc() {
+    echo "TODO: theme_update_havoc not yet implemented"
+}
+
+theme_update_kitty() {
+    killall -SIGUSR1 kitty
+}
+
+case "$TERMINAL" in
+    ("havoc")
+        theme_update_havoc
+    ;;
+    ("kitty")
+        theme_update_kitty
+    ;;
+esac