Add opt-in theme sync to herdr machines (#13430)

* Add a theme-set sample hook that mirrors themes to herdr machines

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Mirror theme changes to herdr machines by default

Replaces the sample hook with omarchy-theme-sync, which omarchy-theme-set
starts detached after every theme change, and a theme-sync-off toggle that
stops a machine from both sending and receiving.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Rename omarchy-theme-sync to omarchy-theme-set-herdr-machines

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Label the toggle Herdr Theme Sync and extract its menu guard

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Answer the Herdr Theme Sync menu guard from omarchy-theme-set-herdr-machines

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Sync herdr machines one at a time and drop the dry run

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Check the theme sync toggle under the lock and stop special-casing this machine

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Make herdr theme sync opt-in

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

bin/omarchy-theme-set

@@ -441,6 +441,9 @@ if [[ $THEME_HEADLESS != "1" ]]; then
   # Call hook on theme set
   omarchy-hook theme-set "$THEME_NAME" >/dev/null
 
+  # Mirror the theme to herdr machines. SSH can take a while, so this never holds up the theme change.
+  setsid omarchy-theme-set-herdr-machines >>"$HOME/.local/state/omarchy/theme-set-herdr-machines.log" 2>&1 </dev/null &
+
   # Warm the background selector's thumbnails. The theme picker keeps its own
   # rows in the shell and refreshes them each time it opens.
   omarchy-theme-bg-cache >/dev/null 2>&1 &