Add Linux deployment scripts

- install.sh: Sets up /opt/kao with systemd service
- uninstall.sh: Clean removal
- Hide message when optimal (only show when something to report)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

index.html

@@ -220,9 +220,9 @@
             emoteEl.style.color = data.color;
             messageEl.style.color = data.color;
 
-            // Show event message if available, otherwise show state
+            // Only show message when there's something to report
             const topEvent = data.active_events && data.active_events[0];
-            messageEl.textContent = (topEvent && topEvent.message) || data.message;
+            messageEl.textContent = (topEvent && topEvent.message) || '';
 
             // Update animation class
             emoteEl.className = '';