refactor(admin): remove DOMContentLoaded listener for watch status initialization

- Remove document.addEventListener("DOMContentLoaded") wrapper for loadWatchStatus()
- Simplify initialization - loadWatchStatus() is now called via Alpine.js x-init
- Reduces 4 lines, keeps same functionality

The loadWatchStatus() function is now triggered by template's x-init directive
instead of a global DOMContentLoaded listener, ensuring it only runs on the
admin page where it's actually needed.

web/src/admin.ts

@@ -328,10 +328,6 @@ async function loadWatchStatus(): Promise<void> {
   }
 }
 
-document.addEventListener("DOMContentLoaded", function () {
-  loadWatchStatus();
-});
-
 let scanPollInterval: ReturnType<typeof setInterval> | undefined = undefined;
 
 function stopScanStatusPolling(): void {