fix: resolve 'outside /home/bernardo' build failure by avoiding directory symlink conflicts

- Update app configurations (btop, kitty, ghostty, opencode, lazygit, tmux) to manage individual files instead of entire directories.
- Use 'recursive = true' for chromium and elephant configurations to allow multiple modules to contribute to the same directory.
- This prevents conflicts when the theme loader tries to add themed config files into directories that were previously managed as monolithic symlinks.

features/apps/chromium/default.nix

@@ -1,5 +1,8 @@
 { config, pkgs, lib, ... }:
 
 {
-  xdg.configFile."chromium".source = ./config;
+  xdg.configFile."chromium/Default" = {
+    source = ./config/Default;
+    recursive = true;
+  };
 }