fix: terminal WebSocket connection — manage xterm containers in JS

- Remove Alpine x-for template for xterm containers (async rendering bug)
- Add static #xterm-wrapper div, JS creates/removes container elements directly
- addTab() uses document.createElement + appendChild for instant DOM
- switchTab() toggles display:block/none, closeTab() removes from DOM
- Add console.log for WebSocket open/close/error debugging
- Terminal now connects on page load

app/backend/views/terminal_content.html

@@ -49,16 +49,8 @@
       </div>
     </div>
 
-    <!-- xterm.js containers — one per tab, shown/hidden by Alpine -->
-    <div class="flex-1 relative min-h-0">
-      <template x-for="(tab, idx) in tabs" :key="tab.id">
-        <div x-show="idx === activeTab"
-             x-cloak
-             class="absolute inset-0">
-          <div :id="'xterm-' + tab.id" class="w-full h-full"></div>
-        </div>
-      </template>
-    </div>
+    <!-- xterm.js containers — managed by JS, not Alpine -->
+    <div id="xterm-wrapper" class="flex-1 relative min-h-0"></div>
 
     <!-- Input prompt -->
     <form @submit.prevent="submitCommand()"