refactor: migrate to template-based theme system, clean up old per-theme configs

- Remove per-theme app configs (alacritty, foot, ghostty, hyprland,
  hyprlock, mako, rofi, swayosd, tmux, walker, waybar, etc.) now
  handled by default/themed/ templates
- Update omarchy scripts (bg-next, list, set) for new template flow
- Update configs: bootstrap, nvim, rofi, tmux, mako
- Tweak installers (02-install-base.sh, btop, desktop, goose, nvim,
  obsidian, theme, tmux)
- Remove obsolete hyprland-rofi-* and hyprland-walker-* scripts
- Update neovim.lua across remaining themes

script/omarchy-theme-list

@@ -1,6 +1,11 @@
 #!/bin/bash
 
-THEMES_DIR="$HOME/.local/share/themes"
-find ${THEMES_DIR}/available/ -mindepth 1 -maxdepth 1 \( -type d -o -type l \) | sort | while read -r path; do
-  echo "$(basename "$path" | sed -E 's/(^|-)([a-z])/\1\u\2/g; s/-/ /g')"
+# omarchy:summary=List available themes
+# omarchy:examples=omarchy theme list | omarchy theme set "Tokyo Night"
+
+{
+  find ~/.config/omarchy/themes/ -mindepth 1 -maxdepth 1 \( -type d -o -type l \) -printf '%f\n'
+  find "${DOTFILES_DIR}/themes/" -mindepth 1 -maxdepth 1 -type d -printf '%f\n'
+} | sort -u | while read -r name; do
+  echo "$name" | sed -E 's/(^|-)([a-z])/\1\u\2/g; s/-/ /g'
 done