Remove empty toggle templates (length-toggle.html, theme-toggle.html,
logo-toggle.html) that were just placeholders. The frontend uses
hx-swap="none" so the response body was always ignored anyway.
Now the handlers:
- Set the preference cookie
- Return 204 No Content immediately
- Hyperscript handles the UI state toggle on the frontend
This removes unnecessary template rendering overhead and cleans up
dead code. Tests updated to expect 204 instead of 200.
juanatsap
e0d445b92a