Lay the fish Module out like ~/.config/fish

Move the Module to modules/fish/fish.nix and mirror a real fish config
directory beside it: config.fish (interactive init), conf.d/done.fish
(the done plugin tuning, now a real conf.d file), and functions/copy.fish.
completions/ and themes/ are omitted as they have no content and git
cannot track empty directories.

modules/fish/conf.d/done.fish

@@ -0,0 +1,3 @@
+# Tune the done plugin: only notify for commands past 10s, at low urgency.
+set -g __done_min_cmd_duration 10000
+set -g __done_notification_urgency_level low

modules/fish/config.fish

@@ -8,10 +8,6 @@ set -gx VISUAL nvim
 set -x MANROFFOPT "-c"
 set -x MANPAGER "sh -c 'col -bx | bat -l man -p'"
 
-# Tune the done plugin: only notify for commands past 10s, at low urgency.
-set -g __done_min_cmd_duration 10000
-set -g __done_notification_urgency_level low
-
 # Prepend ~/.local/bin to PATH when it exists.
 if test -d ~/.local/bin
     fish_add_path ~/.local/bin

modules/fish/fish.nix

@@ -37,6 +37,9 @@ in
         wget # non-interactive HTTP downloader; backs the wget abbreviation
       ];
 
+      # done's tuning lives in its own conf.d snippet, mirroring ~/.config/fish.
+      xdg.configFile."fish/conf.d/done.fish".source = ./conf.d/done.fish;
+
       programs.fish = {
         enable = true;
 
@@ -111,11 +114,11 @@ in
 
           copy = {
             description = "Copy a file, or recursively copy a source directory into a destination";
-            body = builtins.readFile ./fish/copy.fish;
+            body = builtins.readFile ./functions/copy.fish;
           };
         };
 
-        interactiveShellInit = builtins.readFile ./fish/interactive-init.fish;
+        interactiveShellInit = builtins.readFile ./config.fish;
       };
     };
   };